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If you’ve been following terminal-focused installation instructions for Linux applications for a while, you’ve probably come across the curl command at some point or another. cURL is a command-line tool for transferring data with URLs. One of the simplest uses is to download a file via the command line. This is deceptive, however, as cURL is an incredibly powerful tool that can do much more.

What Is cURL?

Originally written by Daniel Sternberg in 1996 to grab financial data from web servers and broadcast it to IRC channels, cURL has evolved to become a powerful tool for getting data without having to use a browser. If you’re always using the terminal, this will be one of the more important tools in your arsenal.

In most Linux distributions, cURL is preinstalled in the system, and you can use it straight away. Even if it is not installed, it is also found in most repositories, so you can easily install it using the Software Center.

For Windows, it does not have a “curl-like” command, and macOS has cURL preinstalled but doesn’t offer quite as many flags as the Linux version.


Before we proceed any further, we have to make sure that cURL is already installed on our system.


In Debian/Ubuntu-based distros, use the following command to install cURL:





In Arch-based distros:





In Fedora/CentOS/RHEL:




curl macOS

For macOS, it is already preinstalled, so you don’t need to do anything.


For Windows 7/10/11, head over to the cURL download page and choose from either the 64-bit or 32-bit packages, according to the architecture you’re running. If you don’t know your architecture, 64-bit is a safe bet, as the vast majority of hardware made after 2006 is on it.

Create a folder either directly on the system drive or in “C:Program Files” and call it “cURL.”

    Go back to the zip file you downloaded, open it, and find “curl.exe” inside the “bin” folder. Copy that to the cURL folder you created. The EXE you copied is completely self-contained and capable of running every permutation you can run on Linux.

    To make this command actually useful, we have to add it to the PATH variable in Windows so that it can run from the command prompt anywhere.

    Every flag in cURL that’s usable in Linux should work in the Windows version.

    Word to the wise: remember that the command prompt should never be confused with Windows Terminal. Windows Terminal comes with its own version of cURL included in the PowerShell that serves similar functionality but works entirely differently.

    Using cURL

    To get started, simply type curl chúng tôi in your terminal and press Enter.

    If you are not getting any output, it is because this site’s server is not configured to respond to random connection requests to its non-www domain. If you polled a server that doesn’t exist or isn’t online, you’d get an error message saying that cURL could not resolve the host.

    If all goes well, you should be staring at a gigantic wall of data. To make that data a bit more usable, we can tell cURL to put it into an HTML file:

    Similarly, you can use the -o flag to achieve the same result:

    When downloading large files, depending on your Internet speed, interruptions can be immensely irritating. Thankfully, cURL has a resume function. Passing the -C flag will take care of this issue in a jiffy.

    To show a real-world example, I interrupted a download of Debian’s testing release ISO on purpose by pressing Ctrl and C in the middle of grabbing it.

    For our next command, are attching the -C flag. For example,

    Downloading More than One File

    Because cURL doesn’t have the most intuitive way to download multiple files, there are two methods, each one with its own compromise.

    If the files you’re downloading are enumerated (e.g., file1, file2, and so on), you can use brackets to get the full range of files and “#” within the output you specify with the -o flag. To make this a bit less confusing, here’s an example:

    Download files that require authentication (for example, when grabbing from a private FTP server) with the -u flag. Every authentication request must be done with the username first and the password second, with a colon separating the two. Here’s an example to make things simple:

    Splitting and Merging Files

    If for any reason you wish to download a large file and split it into chunks, you can do so with cURL’s --range flag. With --range, you must specify the byte you want to start at up to the one you want to finish at. If you do not specify an end to the range, it will just download the rest of the file.

    In the command below, cURL will download the first 100 MB of Arch Linux’s installation image:

    To reunite these files, you’ll have to use the cat command if you’re on Linux or macOS like so:



    b arch.part


    chúng tôi Useful Features

    There are plenty of flags and uses for cURL:

    cURL vs. Wget

    Both released in the same year (1996), cURL and Wget are pretty much sister programs to the casual observer. Dive a little deeper, though, and you can see these two sisters have different purposes.


    It’s fully built from the ground up to grab data from the Internet.

    Doesn’t need the -L or -o flags like cURL; just type wget [url] and go!

    Can download recursively to grab everything in a directory with the -r flag.

    Has all the functions a user needs for daily use and caters to everyday sysadmin tasks.

    (In Linux) Doesn’t need many dependencies; all of them should be available out of the box.


    Expansive repertoire of flags and useful functions for remote retrieval.

    Supports local networking (LDAP) and network printers (Samba).

    Works well with gzip compression libraries.

    Depends on libcurl, which allows developers to write software or bash scripts that include cURL’s functionality.

    In short, Wget is the “everyman’s toolbox” for grabbing stuff from the Internet, while cURL expands on this with more granulated control for power users and system administrators.

    Frequently Asked Questions 1. I got a certificate error in Linux. How do I fix it?

    If you got an error that says something like “peer’s certificate issuer has been marked as not trusted,” the easiest way to fix this is by reinstalling the common certificates package in your distro.

    For Debian/Ubuntu-based systems:



    reinstall ca-certificates

    For Fedora/CentOS/RHEL:


    reinstall ca-certificates

    For Arch-based systems:




    Note that in Arch you may want to clear your package cache using pacman -Scc before reinstalling the certificates package.

    If you still get this error, there may be something wrong on the server’s end.

    2. Is it safe to run cURL and bash commands together?

    It may look a bit scary, but if the people behind the application are trustworthy, it’s very unlikely you’ll break something. Malicious actors are everywhere and can infiltrate repositories like Arch’s AUR, so installing using curl in combination with root access commands isn’t generally more unsafe than doing so through your package manager.

    3. Can I use cURL with Tor?

    Yes! Start Tor Browser (or a standalone tor service) and use the --proxy flag. Tor gives you a local proxy you can use to mask your IP in other applications. Here’s an example of cURL used with Tor:

    Wrapping Up

    cURL has proven resilient amid the changing fabric of the Linux world, keeping its position as an important tool in the terminal user’s arsenal.

    If you are new to the command line, check out some of the most useful Linux commands. If you simply want to search the Web instead of downloading data from the Internet, you can browse on the terminal too.

    Miguel Leiva-Gomez

    Miguel has been a business growth and technology expert for more than a decade and has written software for even longer. From his little castle in Romania, he presents cold and analytical perspectives to things that affect the tech world.

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    You're reading How To Use Curl For Command Line Data Transfer And More

    A Guide To The Command Line For Seo

    Although not an essential skill, the proliferation of coding in SEO has had a fantastic impact on the speed at which tasks can be completed.

    There are, however, some foundational skills that are well worth mastering before learning to code.

    Doing so will enable you to feel far more confident once you begin your journey – and in some cases, you’ll find tasks are easier to accomplish using these approaches anyway!

    In this guide, we’re taking a command line interface (CLI) crash course.

    How Does the Command Line Help in SEO?

    Using the command line for SEO can help you more easily:

    Identify file structure when you want to manipulate data.

    Verify status code when the site is using a service worker.

    Split huge files into more manageable chunks.

    Download or transfer data directly to a server.

    Search for a specific string of characters in a large file.

    Slice data by fields and output to a new file.

    And a lot more you’ll learn about below.

    Specifically, we’ll cover how to navigate a file system without relying on a Graphical User Interface (GUI), and how to create and modify files and directories, manipulate data, and even interact with the web.

    You’ll learn the commands for:

    Changing Directory

    Listing Files


    Making Directories

    Moving Files & Directories

    Removing Files & Directories



    Head & Tail

    Concatenate (Cat)

    Word Count





    Stream Editor





    What is the Command Line?

    A command line interface – also known as a terminal, command prompt, or console – is a text-based interface that can be used to interact with a computer’s operating system (OS).

    CLI’s predate the introduction of graphical interfaces. It’s a living relic of our not-so-distant past, when commands had to be typed out in order for you to navigate and activate a computer’s files.

    Speed: A GUI is effectively a presentation layer that sits on top of a CLI to make things more user-friendly. Ultimately, this means that it will never be as fast, and performing tasks can take significantly longer.

    Necessity: Sometimes it’s only possible to interact with a remote server via a CLI. The same is true for running scripts unless you go to the extra effort of creating a GUI.

    Accessing the Command Line

    The way in which you access the command line is heavily dependent on your operating system.

    On Windows, command line is the command prompt and can be located by searching cmd in the navigation bar.

    It’s important to note that Windows and Mac/Linux differ on many commands, both by name and functionality. This is because Mac and Linux are both UNIX-based operating systems, whereas Windows is… well… Windows.

    We’ll be focusing on UNIX, as the command line is far more developed than the Windows equivalent (unless you use PowerShell) since Windows has always heavily focused on its GUI.

    If you’re a Windows user, to follow along, you’ll need to either:

    Enable Windows Subsystem for Linux.

    Install an emulator such as Git Bash or Cgywin.

    The images in this post are all of Git Bash, which I’ve always used, but your mileage may vary.

    What is the Difference Between the Command Line and Shell?

    One final nuance worth explaining is the difference between the command line and shell.

    A command line is essentially an interface that is used to send commands and display the output, whereas a shell is the interpreter that sits behind it and processes the commands.

    UNIX has a range of different shells available, Bash being the most commonly used (and historically, also the default shell on macOS, until it was switched to Zsh in 2023 when Catalina was released).

    Got it? Great, let’s dig in.

    Note: Square brackets in the examples below signify a placeholder. They are not part of the commands.

    Navigating Files & Directories

    Loading up a non-Windows CLI for the first time can be intimidating. As well as being entirely text-based, it provides limited information on your current working directory — in other words, where you’re presently located.

    To find this out, enter pwd (print working directory).

    In my case, you can see my home directory – indicated by the tilde (~) – is /c/Users/WilliamN.BV.

    To make running scripts and command line utilities easier, you’re best served storing files inside child directories within your home directory. This makes navigating to the files you require as easy as possible.

    Changing Directory

    Cd (change directory) is one of the most commonly used commands and is universal across both Windows and Unix operating systems.

    To navigate to a directory within your current directory, simply type:

    cd [directory]

    To access a subdirectory that sits below this, input the file path:

    cd [directory]/[sub-directory]

    Need to go back to the directory you were previously in? Navigate to it using a hyphen:

    cd -

    Or go to your home directory by entering a tilde:

    cd ~

    On a UNIX based OS, the directory you are currently in is represented by a singular dot, so specifying cd . will run but do nothing.

    Two dots, however, is representative of the parent directory and can be used to efficiently navigate to directories above your existing location.

    Navigate to the directory above your current directory:

    cd ..

    Navigate two levels above your current directory:

    cd ../../

    Navigate to a directory within the directory above:

    cd ../[directory]

    As an example, I have a “Public” folder within /c/Users and can navigate to it by inputting cd ../Public.

    One final thing to note is that directories with spaces in the path need to be escaped when using cd. The easiest way to achieve this is to wrap the folder in quotation marks or apostrophes.

    cd 'my directory' Listing Files

    So far, we’ve managed to work out where we are in our directory tree and navigate around it, but what if we don’t know where specific files and directories are located?

    In those instances, we need to use the list command.

    ls [directory]

    The exact formatting will vary, depending on the command-line interpreter you’re using, but there is almost universally some differentiation for different file types.

    As you can see in the image above, directories are blue in Git Bash and have a trailing slash.

    List the contents of a subdirectory:

    ls [directory]/[sub-directory]

    List only directories in your current directory:

    ls -d */

    List the contents of a directory and its subdirectories:

    ls *

    List a specific type of file using pattern matching:

    ls *.[file-extension] Options

    Up to this point, we’ve gotten by with minimal optional argument usage, as the commands we’ve been running have been relatively simplistic.

    But many commands, such as list, have numerous valuable options that can be specified to modify how a command functions.

    The easiest way to find these out for a command is to type:

    [command] --help

    Useful options for ls include:

    Show all hidden files (which feature a dot before the name):

    ls -a

    Display the size of files:

    ls -s

    Display files in the long listing format (file names, permissions, owner, size and time/date modified):

    ls -l

    Sort by file size:

    ls -S

    Sort by modification time:

    ls -t

    Sort by extension:

    ls -X

    It’s also possible to stack up options if you desire, either by combining these into a singular argument or specifying multiples.

    For example, inputting either of the following will display files – including hidden files – in long listing format, sorted by size.

    ls -aSl ls -a -S -l File

    While ls in long listing format provides high-level information on individual files, it doesn’t provide detailed information about the file type.

    This is where the file command comes in.

    Find the human-readable type of a file:

    file [file-name]

    Find the file types for an entire folder:

    file *

    Find the file type for a specific extension:

    file *.[file-extension]

    Find the mime type for a file:

    file -i [file-name]

    A good SEO use case for the file command is identifying whether CSVs are in the expected format.

    Opening and saving CSVs in Excel can cause havoc with special characters. By using file, it’s easy to establish whether files are encoded with UTF-8, ASCII, or something else.

    It will also highlight the presence of any BOM characters, which can potentially invalidate a chúng tôi or disavow file!

    Creating & Editing Making Directories

    Continually swapping between a GUI and a text-based interface can be a pain. Thankfully, there’s a command for that, too.

    Make a directory:

    mkdir [new-directory]

    Make multiple directories:

    mkdir {one,two,three}

    Make a parent directory and subdirectories:

    mkdir –p directory/directory-2/directory-3

    The -p option enables users to define a directory structure and will create any missing folders required to match it.

    As an example, if we wanted to create a directory to download some compressed log files, a second directory for the uncompressed logs, and a third folder for Googlebot requests, we could run:

    mkdir -p logs-new/uncompressed_logs/googlebot_requests

    In the image above, Ls -R logs is used to display the created directory tree structure.

    Moving Files & Directories

    Move a file:

    mv [file-name] [directory]

    Rename file:

    mv [file1] [file2]

    Move multiple files:

    mv [file-1] [file-2] [directory]

    Move directory:

    mv [directory-1] [directory-2]

    Move files with a specific extension:

    mv *.[file-extension] [directory]

    Add the -i parameter to provide a prompt before overwriting an existing file, and -n to prevent a file being overwritten.

    Shortcuts like the tilde and dot operators that we learned earlier can also be leveraged to move files and folders up the directory structure.

    Removing Files & Directories

    Very much the inverse of the move command is the remove command (rm), which is an easy one to remember because the syntax is almost identical.

    A remove directory command (rmdir) also exists, but this isn’t especially helpful because it only works on empty directories.

    Remove a file:

    rm [file-name]

    Remove multiple files:

    rm [file-1] [file-2] [file-3]

    Remove multiple files with a specific extension:

    rm *.[file-extension]

    Remove an empty directory:

     rm -d [directory]

    Remove a non-empty directory and files:

    rm -r [directory]

    Again, the -i parameter can be specified to provide a prompt before removal on a per-file basis.

    If three or more files are listed, -i will consolidate this down into one prompt.


    The touch command can be used to modify timestamps and create empty files.

    Create a new file without any content:

    touch [file-name]

    Update a files last accessed time:

    touch -a [file-name]

    Update a files last modified time:

    touch -m [file-name]

    Set a specific access and modification time:

    touch -c -t YYDDHHMM [file-name]

    Above is an example timestamp set to 22:59 on 15th December 2023.


    On a UNIX CLI, the copy command (cp) is used solely to copy a file or directory from one place to another.

    This is worth bearing in mind to those more familiar with the Windows command prompt, where the copy command can also be used to combine files.

    Make a copy of a file:

    cp [file-name] [new-file-name]

    Copy file to directory:

    cp [file-name] [directory-name]

    Copy multiple files to directory:

    cp [file-name] [another-file-name] [directory-name]

    Copy all files to destination directory:

     cp -r [existing-directory] [new-directory]

    Copy all files with a specific extension:

    cp *.[file-extension] [directory-name]

    Once again, -i can be used to provide a prompt before a file is overwritten, and -n can be used to prevent this entirely.

    Displaying & Manipulating Head & Tail

    Large files can take a long time to load when using a GUI – if they load at all…

    This is where the head and tail commands come in, allowing you to preview the first – or last! – (n) rows of data.

    It’s incredibly helpful if you’re about to undertake some form of data manipulation but are unsure how the file you are working with is structured.

    Preview the beginning of a file:

    head [file-name]

    Preview the end of a file:

    tail [file-name]

    Both commands display 10 rows of data by default, which can be modified using the -n option.

    head/tail -n 5 [file-name]

    One nuance worth noting is that the tail command comes with a plus option, which prints data starting at a specific line rather than the end.

    tail +5 [file-name] Cat

    The cat command – short for concatenate – is used to read, combine and write files.

    Print the contents of a file:

    cat [file-name]

    Concatenate multiple files into a combined file:

    Combine multiple files with the same extension:

    Concatenate two files without creating a new file:

    A good SEO use case for the cat command is when you’re performing link research. Unless you’re using an API, this will entail downloading multiple exports, all of which will have the same format.

    To combine, pop the exports in a folder and run a cat command with pattern matching on the extension.

    Word Count

    More than just a one-trick pony, the word count command also supports the counting of characters and, more importantly for SEO, lines.

    Count the number of words in a file:

    wc -w [file-name]

    Count the number of characters in a file:

    wc -m [file-name]

    Count the number of lines in a file:

    wc -l [file-name]

    As a basic example, here’s how to count the number of CSV files in a directory:

    Or count the number of lines in multiple files and list the combined total:

    The above shows that a line count on a 73 million row dataset took < 20 seconds.


    The grep command is used to perform a search for a specific string of characters. This is incredibly useful for SEO, where extracting data from large files is an almost daily occurrence. As an example, when parsing log files.

    Extract every line that features a pattern (in this case Googlebot) from a file:

    grep "Googlebot" [file-name]

    Extract every line that features a pattern from multiple files with a specific extension:

    grep "Googlebot" *.[file-extension]

    Extract every line that features a pattern from multiple files with a specific extension and write it to a new file:

    Due to the potential file sizes involved, logs are almost universally stored in one-day increments, so using pattern matching to perform a grep on multiple files is very much the norm.

    Grep’s default behaviour in this instance is to prefix each line with the name of the file.

    access.log-20240623: - - [22/Jun/2024:07:05:46 +0000] "GET / HTTP/1.1" 200 75339 "-" "Googlebot-Image/1.0" - request_time=24142

    This information is totally irrelevant when performing log file analysis for SEO and can thankfully be removed by using the -h option.

    Multiple pattern matches can be performed per line by using the pipe command. A good use case for this is when requests for multiple domains are stored in the same location, and you only want one.

    Extract every line that features two patterns from multiple files with a specific extension and write it to a new file:

    To count the occurrences of a pattern in a file, use the -c option. It’s worth bearing in mind that this will perform a count per file though, as with wc -l. To get the total matches across multiple files, combine with the cat command.

    Extract every line that does not feature a pattern from a file:

    grep -v "pattern" [file-name]

    Extract every line that features a pattern from a file (case insensitive):

    grep -i "pattern" [file-name]

    Extract every line that features a pattern from a file using Regex:

    grep -E "regex-pattern" [file-name] Sort

    Of limited usage on its own, sort can be combined with other commands to sort the output alphabetically or numerically.

    Order alphabetically and output to a new file:

    Reverse the order and output to a new file:

    Order numerically and output to a new file:

    Order alphabetically on the n column (in this instance 3) and output to a new file:

    Order using multiple columns and output to a new file:

    Sort can also be used to remove duplicate lines:

    Or stacked with word count to get a tally of unique lines within a file:


    Struggling to open something? The split command is perfect for separating huge files into more manageable chunks.

    Split a file into smaller chunks (1000 lines by default):

    split [file-name]

    Split a file into smaller chunks with a specified number of lines:

    split -l[number] [file-name]

    Split a file into a given number of chunks:

    split -n[number] file-name]

    Split a file into smaller chunks with a specified file size:

    split -b[bytes] [file-name]

    Files can also be split based on kilobytes, megabytes and gigabytes:

    split -b 100K [file-name] split -b 10M [file-name] split -b 10G [file-name]

    While the above commands will split a file, they will not automatically maintain the files extension. To do so, use the --additional-suffix option.

    Here’s a more practical example of how to split a large CSV file into 100MB chunks using this option. In it, we’ve also specified the -d option and added a custom suffix. This means that the output files will follow a naming convention of ‘logs_[number]’, rather than alphabetic characters.

    split -d -b 100M --additional-suffix=.csv chúng tôi logs_

    When testing a script, it’s often helpful to grab a random data sample from a file. Unfortunately, the split command does not have an option for this. Instead, use shuf.


    Cut allows you to access parts of the lines of an input file and output the data to a new file. Although it can also be used to slice by bytes and characters, the most useful application for SEO is slicing data by fields.

    Slice file by field:

    cut -f [number] [file-name]

    Slice file by multiple fields:

    cut -f [number-1],[number-2] [file-name]

    Slice file by a range of fields:

    cut -f [number-1]-[number-2] [file-name]

    Slice file by a range of fields (from the selected number to the end of the line):

    cut -f [number]- [file-name]

    Cut slices using the tab delimiter by default, but this can be changed using the -d option (e.g. space):

    cut -d " " -f [number] [file-name]

    It’s also possible to stack multiple ranges together. To provide a more practical illustration, if you wanted to extract specific columns from multiple links files that share the same format:

    Sed (Stream Editor)

    The sed command can perform a range of useful text transformations, including filtering, find and replace, insertions and deletions.

    View lines within the middle of a document (which isn’t supported by head and tail):

    sed -n '[number-1],[number-2]p' [file-name]

    Perform a find and replace and save the output:

    Perform a find and replace save inplace:

    sed -i 's/[find-text]/[replace-with]/g' [file-name]

    Perform a find, replace with nothing and save the output:

    Find and delete lines with a specific pattern, saving the output:

    Find and delete blank lines (using Regex), saving the output:

    Delete spaces at the end of lines of text and save the output:

    Run multiple find and replaces on a file and save the output:


    For really heavy-duty data manipulation using the command line, learn how to use awk. Awk is a scripting language in its own right, and is capable of a range of different transformations.

    Count the unique values in a column:

    Below shows count of status codes in a log file.

    Perform a find and replace on a column and save the output:

    awk -F '[delimiter]' '{ gsub("pattern", "new-pattern", $[column-number]) ; print}'

    Filter rows down based on a column meeting a condition (greater than):

    Filter rows down using pattern matching on a column (contains):

    awk -F '[delimiter]' '$[column-number] ~ /[pattern]/' [file-name]

    Count word frequency within a file:

    awk 'BEGIN {FS="[^a-zA-Z]+" } { for (i=1; i<=NF; i++) words[tolower($i)]++ } END { for (i in words) print i, words[i] }' *

    As you can see in the examples above, the syntax for an awk query is a bit more complex than what we’ve covered previously.

    Awk supports many constructs from other programming languages, including if statements and loops, but if you’re more familiar with another language, this may be the complexity level at which it’s worth transitioning over.

    That said, it’s always worth doing a quick search for an awk solution first.

    Interacting With the Web Curl (Client URL)

    Curl is a command line utility that allows users to download data from, or transfer data to, a server. This makes it incredibly useful for SEO, where we have to continually check status codes, headers and compare server and client-side HTML.

    Get the contents of a URL:

    curl [url]

    Save the contents of a URL to a file:

    curl -o [file-name] [url]

    Download a list of URLs from a file:

     xargs -n 1 curl -O < [file-of-urls]

    Use curl with the -I option to display only the headers and status code:

    curl -I [url]

    Curl -I is a great way to verify status codes when a site is using a service worker, which often conflict with browser extensions.

    It’s also excellent for verifying if a CDN’s bot mitigation is causing issues when you’re attempting to crawl a site. If it is, you’ll almost certainly be served a 403 (Forbidden) status code.

    To fully replicate a redirect tracing extension, enable follow redirects with the -L option:

    curl -LI [url]

    Get the contents of a URL using a custom user agent:

    curl -A "User-Agent" [url]

    Use a different request method with a custom header:

    curl -X POST -H "Content-type: application/json" [url]

    Test whether a URL supports a protocol (e.g. whether a site supports HTTP2, or a site on HTTP2 is backwards-compatible with HTTP/1.1):


    Wget performs a similar function to curl but features recursive downloading, making it the better choice when transferring a larger number of files (or an entire website!).

    Wget is included in most distributions automatically, but if you’re using GIT Bash, you’ll have to install it.

    Download a file:

    wget [url]

    Download a list of URLs in a text file:

    wget -i [file-name].txt

    Download an entire website:

    wget -r [url]

    By default, wget will only download pages recursively up to five levels deep. Extend this using the -l option:

    wget -r -l [number] [url]

    Or, if you’re feeling brave, enable infinite recursion:

    wget -r -l inf [url]

    If you want to download a local copy of a site – with the links updated to reference the local versions – then use the mirror option instead:

    wget -m [url]

    You can also restrict the types of files downloaded. If, for instance, you only wanted JPGs:

    wget -r -A jpg,jpeg [url]

    Or wanted to download all images on a website to a single directory, including those on a CDN, ignoring the robots.txt:

    wget -r -l inf -nd -H -p -A jpg,jpeg,png,gif -e robots=off [url] Cleaning Your Output

    To finish things off, a bit of housekeeping is on order.

    If you’ve been following along and trying out commands, the chances are that your command line is starting to look messy. Thankfully, clearing – or quitting! – the interface is very simple.

    Clear the output of the command line:


    Exit the command line:

    exit Taking Things Further

    The above commands will have given you a good idea of the types of tasks you can accomplish using the command line, but this is really just a jumping-off point.

    With the ability to chain commands together, the possibilities are virtually endless – especially if you start exploring Bash scripting.

    To provide a few more ideas, you could:

    Automate Screaming Frog.

    Run web performance tests like Lighthouse in bulk.

    Perform en-masse image compression.

    Or publish a website using a JAMstack architecture.

    Lastly, a degree of competency using the command line is essential when you begin coding.

    It’s a skill you’ll use constantly when navigating to, and running, your scripts.

    And with the popularity of Git repositories such as GitHub and Gitlab, I hope you’ll use it to contribute to projects and share your work with the world, as well!

    More Resources:

    Featured image: fatmawati achmad zaenuri/Shutterstock

    The Data Transfer Project’s Big

    The Data Transfer Project addresses one pain point we all experience on our phones: moving our stuff around. While it’s certainly gotten easier over the years to share individual photos, songs, and files from one app to another, shifting large chunks of data or entire libraries and histories between services is often an exercise in futility, even with hundreds of gigabytes of cloud storage at our disposal.

    But while the four founding members are certainly big enough to get the Data Transfer Project off the ground, it’s missing the support of the biggest player of all: Apple. And without the iPhone maker on board, it’s going to be a tougher sell than it should be.

    Share and share alike

    On the surface, the Data Transfer Project has a very simple goal that all providers and developers should support: portability, privacy, and interoperability. In the announcement, Google, Facebook, Twitter, and Microsoft served up this clear mission statement: Making it easier for individuals to choose among services facilitates competition, empowers individuals to try new services, and enables them to choose the offering that best suits their needs.


    iPhone users should get the same Data Transfer experience as Android users.

    The timing of the announcement isn’t accidental. While the group was officially formed last year, 2023 has been a troubling year for data and privacy, particularly with regard to three of the companies here. Facebook, Twitter, and Google have each taken very public lumps over the handling of user data. Most recently, the European Union implemented a stringent set of laws governing privacy rights and adding layers of transparency for users.

    If nothing else, the Data Transfer Project is a public commitment to free users’ data from any one service and respect the right to move it between apps. In simple terms, your Facebook photos are just photos, so when the next big social thing comes along, you won’t need to rebuild your entire digital profile.

    The benefit applies to non-social situations as well. As the group explains in its white paper: “A user doesn’t agree with the privacy policy of their music service. They want to stop using it immediately, but don’t want to lose the playlists they have created. Using this open-source software, they could use the export functionality of the original provider to save a copy of their playlists to the cloud. This enables them to import the playlists to a new provider, or multiple providers, once they decide on a new service.”

    Opening the walled garden

    The aim of the Data Transfer Project is something that simultaneously agrees and disagrees with Apple’s core philosophies. On the one hand, Apple promotes ease-of-use and interoperability among all of its products. The company is constantly working to break down barriers so our data can jump seamlessly from one device and app to the next.


    If Apple is truly serious about privacy, it needs to sign on board with the Data Transfer Project.

    But if Apple is truly committed to privacy—and not just Apple device privacy—it needs to take a stand here. While the lock-in inherent to Apple’s ecosystem is often derided, the fact of the matter is, a walled garden is a nice place to play. The devices all work well together, and they’re encrypted and secure and receive the latest security patches and updates. That’s why many people would be plenty happy to stay, even if Apple made it easier to leave by supporting the Data Transfer Project.

    As it stands, the Data Transfer Project is an ambitious project that won’t see its full potential without the support of Apple. If the ease-of-use and privacy gains it delivers stops at the iPhone, the rest of the industry will be reluctant to join forces, even with the might of Google, Microsoft, and Facebook behind it. And Apple doesn’t need to tear down its walled garden to support it. It merely needs to put a key under the doormat.

    How To Use Sqlite To Store Data For Your Android App

    Preparation Extending “SQLiteOpenHelper”

    We create a class, called ExampleDBHelper, that extends SQLiteOpenHelper. We begin by defining the database, tables and columns as constants. This is always a good idea. If any of these names get changed, rather than hunting through the source for all occurrences, we simply change it once. Take special notice of the column called “_id” (PERSON_COLUMN_ID). This column has special significance which will be discussed below.


    public static final String DATABASE_NAME = "SQLiteExample.db"; private static final int DATABASE_VERSION = 1; public static final String PERSON_TABLE_NAME = "person"; public static final String PERSON_COLUMN_ID = "_id"; public static final String PERSON_COLUMN_NAME = "name"; public static final String PERSON_COLUMN_GENDER = "gender"; public static final String PERSON_COLUMN_AGE = "age";

    In the constructor, we call SQLiteOpenHelper’s constructor, passing it the application context, the database name, an SQLiteDatabase.CursorFactory (we actually pass a null object here), and the database version. This constructor handles the creation or upgrade of the database. The database version should begin from 1, and increase linearly, whenever you modify the database schema.


    public ExampleDBHelper(Context context) { super(context, DATABASE_NAME , null, DATABASE_VERSION); }

    The onCreate() is called whenever a new database is created. Here, you specify each table schema. In our example app, we have only one table.


    @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE " + PERSON_TABLE_NAME + "(" + PERSON_COLUMN_ID + " INTEGER PRIMARY KEY, " + PERSON_COLUMN_NAME + " TEXT, " + PERSON_COLUMN_GENDER + " TEXT, " + PERSON_COLUMN_AGE + " INTEGER)" ); }

    The overridden onUpgrade() method is called whenever the database needs to be upgraded (i.e. when the version has changed). Here, you should drop and/or add tables, or migrate data to new tables, or whatever else needs to be done to move from the previous database schema to the new schema. In our example, we simply drop the existing “person” table, and then call onCreate() to recreate it. I doubt you would want to do this with real user data.


    @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS " + PERSON_TABLE_NAME); onCreate(db); }

    For the sample application, we want the ExampleDBHelper class to handle all data insertion, deletion, updates and views (basically all queries to the database must be through ExampleDBHelper). So we define appropriate methods for each of these scenarios.

    To insert a new Person, we use the creatively named insertPerson() method. We use the SQLiteOpenHelper method getWritableDatabase() to get an SQLiteDatabase object reference to our already created database. The Person details are stored in a ContentValues object, with the appropriate column name as key, and corresponding data as value. We then call SQLiteDatabase’s insert method with the person table name, and the ContentValues object. NOTE that we left out the PERSON_COLUMN_ID column, which was specified as a primary key. It automatically increments.


    public boolean insertPerson(String name, String gender, int age) { SQLiteDatabase db = getWritableDatabase(); ContentValues contentValues = new ContentValues(); contentValues.put(PERSON_COLUMN_NAME, name); contentValues.put(PERSON_COLUMN_GENDER, gender); contentValues.put(PERSON_COLUMN_AGE, age); db.insert(PERSON_TABLE_NAME, null, contentValues); return true; SQLiteDatabase db = this.getWritableDatabase(); ContentValues contentValues = new ContentValues(); contentValues.put(PERSON_COLUMN_NAME, name); contentValues.put(PERSON_COLUMN_GENDER, gender); contentValues.put(PERSON_COLUMN_AGE, age); db.update(PERSON_TABLE_NAME, contentValues, PERSON_COLUMN_ID + " = ? ", new String[] { Integer.toString(id) } ); return true; SQLiteDatabase db = this.getReadableDatabase(); Cursor res = db.rawQuery( "SELECT * FROM " + PERSON_TABLE_NAME + " WHERE " + PERSON_COLUMN_ID + "=?", new String[] { Integer.toString(id) } ); return res; } public Cursor getAllPersons() { SQLiteDatabase db = this.getReadableDatabase(); Cursor res = db.rawQuery( "SELECT * FROM " + PERSON_TABLE_NAME, null ); return res; }

    Deleting data is also pretty straightforward. SQLiteDatabase has a delete() method that takes the table name to delete from, and optional whereClause and whereArgs. NOTE: Be very careful when writing this, as passing null in the whereClause would delete all rows.


    public Integer deletePerson(Integer id) { SQLiteDatabase db = this.getWritableDatabase(); return db.delete(PERSON_TABLE_NAME, PERSON_COLUMN_ID + " = ? ", new String[] { Integer.toString(id) }); android:orientation="horizontal" android:layout_width="match_parent" <TextView android:id="@+id/personID" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="@dimen/activity_vertical_margin" <TextView android:id="@+id/personName" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:padding="@dimen/activity_vertical_margin" The complete MainActivity code follows:


    public class MainActivity extends ActionBarActivity { public final static String KEY_EXTRA_CONTACT_ID = "KEY_EXTRA_CONTACT_ID"; private ListView listView; ExampleDBHelper dbHelper; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button button = (Button) findViewById(; @Override Intent intent = new Intent(MainActivity.this, CreateOrEditActivity.class); intent.putExtra(KEY_EXTRA_CONTACT_ID, 0); startActivity(intent); } }); dbHelper = new ExampleDBHelper(this); final Cursor cursor = dbHelper.getAllPersons(); String [] columns = new String[] { ExampleDBHelper.PERSON_COLUMN_ID, ExampleDBHelper.PERSON_COLUMN_NAME }; int [] widgets = new int[] {, }; SimpleCursorAdapter cursorAdapter = new SimpleCursorAdapter(this, R.layout.person_info, cursor, columns, widgets, 0); listView = (ListView)findViewById(; listView.setAdapter(cursorAdapter); @Override int position, long id) { Cursor itemCursor = (Cursor) MainActivity.this.listView.getItemAtPosition(position); int personID = itemCursor.getInt(itemCursor.getColumnIndex(ExampleDBHelper.PERSON_COLUMN_ID)); Intent intent = new Intent(getApplicationContext(), CreateOrEditActivity.class); intent.putExtra(KEY_EXTRA_CONTACT_ID, personID); startActivity(intent); } }); } }

    CreateOrEditActivity is a little bit more involved. The Activity allows creating, editing and deleting persons. It also changes its UI based on what action is to be performed. Because of it’s length, we shall only show and discuss the parts relevant to database interaction.

    In onCreate(), if we receive a personID, we call dbHelper.getPerson() with that ID, and then populate the fields with the person details:


    Cursor rs = dbHelper.getPerson(personID); rs.moveToFirst(); String personName = rs.getString(rs.getColumnIndex(ExampleDBHelper.PERSON_COLUMN_NAME)); String personGender = rs.getString(rs.getColumnIndex(ExampleDBHelper.PERSON_COLUMN_GENDER)); int personAge = rs.getInt(rs.getColumnIndex(ExampleDBHelper.PERSON_COLUMN_AGE)); if (!rs.isClosed()) { rs.close();


    case AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage(R.string.deletePerson) dbHelper.deletePerson(personID); Toast.makeText(getApplicationContext(), "Deleted Successfully", Toast.LENGTH_SHORT).show(); Intent intent = new Intent(getApplicationContext(), MainActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); } }) } }); AlertDialog d = builder.create(); d.setTitle("Delete Person?");; return;

    Finally, we implemented a persistPerson() method that checks if we require a person creation or update.


    public void persistPerson() { if(dbHelper.updatePerson(personID, nameEditText.getText().toString(), genderEditText.getText().toString(), Integer.parseInt(ageEditText.getText().toString()))) { Toast.makeText(getApplicationContext(), "Person Update Successful", Toast.LENGTH_SHORT).show(); Intent intent = new Intent(getApplicationContext(), MainActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); } else { Toast.makeText(getApplicationContext(), "Person Update Failed", Toast.LENGTH_SHORT).show(); } } else { if(dbHelper.insertPerson(nameEditText.getText().toString(), genderEditText.getText().toString(), Integer.parseInt(ageEditText.getText().toString()))) { Toast.makeText(getApplicationContext(), "Person Inserted", Toast.LENGTH_SHORT).show(); } else{ Toast.makeText(getApplicationContext(), "Could not Insert person", Toast.LENGTH_SHORT).show(); } Intent intent = new Intent(getApplicationContext(), MainActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); } } Conclusion

    Android Developer Newsletter

    How To Use ‘Single Player’ Cheat Codes In Valheim. (Console Command)

    If you are playing Valheim in early access at the moment and are absolutely loving it! This guide will take you through all of the games single-player cheat codes. These are legitimate cheats added to the game by the devs, so don’t feel guilty about using them. None of them will work within the multiplayer aspect of the game. And just to make things clear, we ABSOLUTELY HATE ONLINE CHEATERS!

    Related: How to fix Genshin Impact not visible in OBS Game Capture Mode.

    One of the main things that make Valheim so unique is its single and multiplayer formatting, which gives both single-player fans and multiplayer fans their own in-game experience. As someone who’s always been a huge fan of co-op, Valheim’s 2-10 player co-op system is its best feature. Good co-op games are a dime a dozen and Valheim finally fill a void that has existed for a long time.

    Full list of Valheim cheats and console commands.

    What it does


    This activates God Mode, which makes you indestructible.


    This activates the free camera.

    ffsmooth 1

    Adds smooth movements to free camera.

    ffsmooth 0

    Resets smooth movements to normal.


    This kills all nearby enemies. Your personal kill switch.


    This tames any boars, wolves, or lox in the immediate area.


    This reveals the entire map. Potential spoilers for using this!


    Unsee everything you saw


    Show the player’s coordinates.

    goto [x,z]

    This will teleport you to a specified coordinates.


    This sets your spawn location. Your bed away from your bed.

    event [name]

    Starts a named event.


    Stops the current event.


    Starts a random event.

    raiseskill [skill] [amount]

    Raises the specified skill. You can choose an amount between 1 and 100.


    Resets all of your character data. A fresh start.


    Toggles dps debug on and off.


    Forces the game to save.

    players [nr]

    Adjusts the difficulty scale. Set it to 0 to totally reset the difficulty.


    Removes all items dropped in the immediate area. Perfect for clean up unwanted materials.

    All Valheim server admin console commands.


    What it does


    This shows all of the available admin commands.

    kick [name/ip/userID]

    This will kick a specified player.

    ban [name/ip/userID]

    This will ban a specified player.

    unban [ip/userID]

    This will unban a specified player.


    Pings the server to measure latency.

    lodbias [number]

    Sets the draw distance for the server. The number can be set between 1 and 5.


    Post your current system information.

    It’s worth noting that while all of these cheat codes and commands work for now in early access, they may not continue to work in future releases of the game. That said, it’s kinda cool to have some old school style cheat codes for games again. 

    How Small Businesses Can Use Marketing Data For Growth

    Over the last few years, there has been an unprecedented explosion of data. As a result of this, data analytics has become a growing field and many businesses are choosing to heavily invest in professionals of this industry to take their organizations to the next level.

    However, despite this growing interest in data, there is still a large disconnect between the sheer volume of data being created and the number of organizations making use of this data.

    Certain aspects of marketing data can provide valuable information to companies, such as campaign tracking or general web traffic, yet few small businesses make use of this information.

    Here, we’ll talk about how you can use marketing data to improve your marketing strategies and grow your business.

    Identify the Right Marketing Data

    One big reason that marketing data is not used effectively by many small businesses is due to a lack of understanding regarding the importance of that data. Data analytics isn’t a new field, yet many small business owners fail to see how they can access and use their marketing data.

    Related: Use data to create a content map that converts more customers.

    Some organizations today focus on older forms of data to pull consumer analytics from, but this data isn’t as representative as more modern data sources. Despite the fact that many businesses make use of the wrong data, the importance of targeting the right data is not commonly known.

    So, how can you find the right data to target? It’s essential to place an emphasis on the collection of data that deals with consumer traffic, conversion rates, and marketing growth.

    Image Source

    And, the type of data that you need to collect may vary by marketing type. For instance, the marketing data you collect from PPC campaigns could vary from your SEO metrics.

    Related: Find out the 29 marketing metrics you need to know to track every strategy.

    You can also look at the sources of data you can collect, including first-party data, which can help you boost your chances for marketing success.

    Focus on Marketing Data that Taps Into the Consumer Mindset

    Regardless of if you choose to invest in your own data analytics or outsource the job, understanding the consumer mindset is everything. Another reason small businesses overlook key data is that they retain the mindset of a seller. Put yourself in the shoes of a potential consumer and you’ll be able to identify more data points to target.

    Almost every customer has the option to leave a review after purchase, and reviews can provide valuable marketing data for your small business. But, you can also take it a step further and reach out to consumers for case studies, which can not only give you coveted marketing data to drive growth but can create validation for your business.

    Data shows that case studies are an extremely important part of the consideration stage in the buyer’s journey that can make or break a purchase decision.

    Image Source

    Adding this simple validation to your website can help convince potential customers that you are a reliable organization, while also helping you to build a connection with previous customers and have them potentially make another purchase, which is a big way that marketing data can help propel your business toward growth.

    Related: Own or run a finance business? Get data-backed finance marketing strategies built around consumer behavior.

    Determine the Best Way to Collect Marketing Data

    After determining and outlining the most important types of data for your organization, collecting said data is the next course of action. For small or even mid-sized businesses, this can seem like a tall order. Creating a new division within your organization dedicated to data collection and analytics can be expensive and time-consuming, which is why relying on third-party data analytics teams is typically a smarter move — especially for small businesses.

    After all, your entire organization doesn’t need to become an expert in data analytics if you choose to partner with experts in the field. Many marketing partners offer prominent features such as digital presence building and outreach marketing services from which they can collect and synthesize important marketing data in the form of reporting dashboards — or they can even tie the information into your CRM.

    Utilize Data to Create Personalized Campaigns

    Based on the data collected either by yourself or by your marketing agency, you can then personalize your outreach to customers. By personalizing your campaigns based on marketing data you can optimize each message sent to a customer and increase the odds of getting engagement.

    Image Source

    Remember that personalization is one of the most important aspects of modern marketing and helps to build trust. And, personalization is only possible with accurate and complete marketing data.

    Get Started Analyzing Your Marketing Data

    As technology continues to develop, the data floating around the internet will inevitably increase. Taking the time to learn how to sift through that data and partnering with effective professionals can help accelerate your business growth faster than ever before.

    About the Author Guest Author

    Our guest authors are industry experts, marketers, or business owners who cover a range of topics from sales, marketing, data, and entrepreneurship.

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