Trending March 2024 # Understanding Pipes And Redirection For The Linux Command Line # Suggested April 2024 # Top 6 Popular

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On all Unix-like operating systems, like Linux and FreeBSD, the output from a command line program automatically goes to a place known as standard output (stdout). By default, standard out is the screen (the console) but that can be changed using pipes and redirection. Likewise the keyboard is considered the standard input (stdin) and as with standard out, it can be changed.

Pipes

Pipes allow you to funnel the output from one command into another where it will be used as the input. In other words, the standard output from one program becomes the standard input for another.

The “more” command takes the standard input and paginates it on the standard output (the screen). This means that if a command displays more information than can be shown on one screen, the “more” program will pause after the first screen full (page) and wait for the user to press SPACE to see the next page or RETURN to see the next line.

Here is an example which will list all the files, with details (-la) in the /dev directory and pipe the output to more. The /dev directory should have dozens of files and hence ensure that more needs to paginate.

Notice the --More-- prompt at the bottom of the screen. Press SPACE to see the next page and keep pressing SPACE until the output is finished.

Here is another pipe example, this time using the “wc” (word count) tool.

The In Depth Look at Linux’s Archiving and Compression Commands tutorial has an example using tar and 7-Zip together:

Redirection

The cat command can be used to create a file using redirection, for example:

Conclusion

Many of Linux command line programs are designed to work with redirection and pipes, try experimenting with them and see how they interact. For example the output of the ps command, which lists the current processes, can be piped into grep. See if you can work out how to list the processes owned by root.

Gary Sims

Gary has been a technical writer, author and blogger since 2003. He is an expert in open source systems (including Linux), system administration, system security and networking protocols. He also knows several programming languages, as he was previously a software engineer for 10 years. He has a Bachelor of Science in business information systems from a UK University.

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5 Linux Command Line Based Tools For Downloading Files And Browsing Websites

Linux is a popular operating system among developers and tech enthusiasts. It offers a powerful command-line interface (CLI) that can be used to accomplish various tasks. One of essential tasks that most Linux users need to perform is downloading files and browsing websites. In this article, we will discuss five Linux command-line based tools for downloading files and browsing websites.

Wget

wget is a free utility for downloading files from web. It is a command-line tool that can be used to download files over HTTP, HTTPS, and FTP protocols. With wget, you can download files from a single URL or multiple URLs. You can also use it to mirror entire websites or parts of them. syntax for using wget is straightforward −

wget [options] [URL]

For example, to download a file from a website, you can use following command −

You can also use wget to download multiple files at once. For example, to download all PDF files from a website, you can use following command −

This command will download all PDF files from chúng tôi website.

Curl

curl is another popular command-line tool for downloading files from web. It supports various protocols, including HTTP, HTTPS, FTP, and SFTP. You can use curl to download files from a single URL or multiple URLs. You can also use it to upload files to a server. syntax for using curl is as follows −

curl [options] [URL]

For example, to download a file from a website, you can use following command −

This command will download file and save it with same name as on website. If you want to save it with a different name, you can use -o option, as shown below −

Lynx

lynx is a text-based web browser that runs in terminal. It is a command-line tool that can be used to browse web, read news, and view HTML files. Lynx does not support graphics or JavaScript, so it is a fast and lightweight browser. It can be used to browse web even on slow internet connections. syntax for using lynx is as follows −

lynx [options] [URL]

For example, to browse chúng tôi website, you can use following command −

Lynx supports various keyboard shortcuts for navigation, such as arrow keys for scrolling, Enter for following links, and Q for quitting browser.

Elinks elinks [options] [URL]

For example, to browse chúng tôi website, you can use following command −

Elinks supports various keyboard shortcuts for navigation, such as arrow keys for scrolling, Enter for following links, and Ctrl+T for opening a new tab.

W3m

w3m is a text-based web browser that runs in terminal. It is a simple and lightweight browser that supports basic web browsing features. W3m can be used to browse web, read news, and view HTML files. It supports mouse support and tabbed browsing. syntax for using w3m is as follows −

w3m [options] [URL]

For example, to browse chúng tôi website, you can use following command −

W3m supports various keyboard shortcuts for navigation, such as arrow keys for scrolling, Enter for following links, and Ctrl+T for opening a new tab.

Aria2

aria2 is a lightweight and powerful command-line download manager that supports various protocols, including HTTP, HTTPS, FTP, and BitTorrent. It can download files from multiple sources simultaneously, which makes it a great tool for downloading large files. syntax for using aria2 is as follows −

aria2c [options] [URL]

For example, to download a file from a website using aria2, you can use following command −

Youtube-dl

youtube-dl is a command-line utility that can be used to download videos from various websites, including YouTube, Vimeo, and Dailymotion. It supports various formats, including MP4, WebM, and FLV. syntax for using youtube-dl is as follows −

youtube-dl [options] [URL]

For example, to download a YouTube video using youtube-dl, you can use following command −

Httrack

httrack is a free and open-source website copier that can be used to download entire websites to your local machine. It supports various options, including mirror mode, update mode, and resume mode. syntax for using httrack is as follows −

httrack [options] [URL]

For example, to download a website using httrack, you can use following command −

These are some additional Linux command-line based tools that can be used for downloading files and browsing websites. Each tool has its own set of features and capabilities, and you should choose tool that best suits your needs.

Conclusion

In conclusion, these are five Linux command-line based tools that can be used for downloading files and browsing websites. Wget and curl are great tools for downloading files from web, while lynx, elinks, and w3m are text-based web browsers that can be used to browse web in terminal. These tools are lightweight and can be used even on slow internet connections. By using these tools, Linux users can accomplish various tasks in terminal, without need for a graphical user interface.

Monitor Progress Of A Linux Command Line Operation

If you’re a Linux system admin, there’s no doubt that you must be spending most of your work time on the command line – installing and removing packages; monitoring system stats; copying, moving, deleting stuff; debugging problems; and more. There are times when you fire a command, and it takes a while before the operation completes. However, there are also times when the command you executed just hangs, leaving you guessing as to what’s actually happening behind the scenes.

Usually, Linux commands provide no information related to the progress of the ongoing operation, something that is very important especially when you have limited time. However, that doesn’t mean you’re helpless – there exists a command, dubbed pv, that displays useful progress information related to the ongoing command line operation. In this article we will discuss this command as well as its features through some easy-to-understand examples.

PV Command

Developed by Andrew Wood, PV – which stands for Pipe Viewer – displays information related to the progress of data through a pipeline. The information includes time elapsed, percentage completed (with progress bar), current throughput rate, total data transferred, and ETA.

“To use it, insert it in a pipeline between two processes, with the appropriate options. Its standard input will be passed through to its standard output and progress will be shown on standard error,”

The above explains the command’s man page.

Download and Installation

Users of Debian-based systems like Ubuntu can easily install the utility by running the following command in terminal:

sudo

apt-get install

pv

If you’re using any other Linux distro, you can install the command using the package manager installed on your system. Once installed successfully you can use the command line utility in various scenarios (see the following section). It’s worth mentioning that pv version 1.2.0 has been used in all the examples mentioned in this article.

Features and Usage

A very common scenario that probably most of us (who work on the command line in Linux) would relate to is copying a movie file from a USB drive to your computer. If you try to complete the aforementioned operation using the cp command, you’ll have to blindly wait until the copying is complete or some error is thrown.

However, the pv command can be helpful in this case. Here is an example:

So, as you can see above, the command shows a lot of useful information related to the ongoing operation, including the amount of data that has been transferred, time elapsed, rate of transfer, progress bar, progress in percentage, and the amount of time left.

The pv command provides various display switches. For example, you can use -p for displaying percentage, -t for timer, -r for rate of transfer, -e for eta, and -b for byte counter. The good thing is that you won’t have to remember any of them, as all of them are enabled by default. However, should you exclusively require information related to only a particular display switch in the output, you can pass that switch in the pv command.

There’s also a -n display switch that allows the command to display an integer percentage, one per line on standard error, instead of the regular visual progress indicator. The following is an example of this switch in action:

This particular display switch is suitable in scenarios where you want to pipe the output into the dialog command.

Moving on, there’s also a command line option, -L, that lets you modify the data transfer rate of the pv command. For example, I used -L to limit the data transfer rate to 2MB/s.

As can be seen in the screenshot above, the data transfer rate was capped according to my direction.

Another scenario where pv can help is while compressing files. Here is an example of how you can use this command while compressing files using Gzip:

Conclusion

As you have observed, pv is a useful little utility that could help you save your precious time in case a command line operation isn’t behaving as expected. Plus, the information it displays can also be used in shell scripts. I’d strongly recommend this command; it’s worth giving a try.

Himanshu Arora

Himanshu Arora is a freelance technical writer by profession but a software programmer and Linux researcher at heart. He covers software tutorials, reviews, tips/tricks, and more. Some of his articles have been featured on IBM developerworks, ComputerWorld, and in Linux Journal.

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Command Line New Features In Windows 10

Many changes were made in Windows 10 but some changes haven’t been discussed much. One of those changes has to do with the Command Line, and as such, we will focus on that.

Improvements to the Command Line in Windows 10

Now, there are several new changes Microsoft has done to the Command Line, and from what we can tell, developers and those regular folks who prefer to use the Command Line for various reasons, have found the changes quite pleasing.

Without wasting any time, then, let’s talk about some of the new stuff.

Tar and Curl support

As for CURL, well, it’s a CLI tool that allows for sending and receiving files. It supports several protocols, and guess what? Users can easily make an HTTP request and view the response from the Command Line.

Background tasks

It was always possible for Windows 10 users to run a background task, but the problem is, but the WSL console had to be kept running, or the task would end. With this newest update, users can run their background task without worrying about the WSL console.

You see, if its clothes, the tasks will continue to work, and that’s great.

Support for Unix Sockets

Here’s the thing, Unix Sockets were not supported on Windows 10, but that has all changed with the v1803 update. Additionally, it’s possible to communicate over Unix sockets between Windows and WSL.

There are several rules as to how this must work, so Microsoft requires you to read the information available via a blog post.

OpenSSH-based client and server

The OpenBSD Foundation were the ones who created the OpenSSH suite of tools. We understand this suite of tools were created for remote command-line administration, public/private key management, secure file transfers, and more.

With this new update, users now have the chance to play around with the SSH client and key agent. As for the SSH server, it’s an optional feature that is available on-demand.

These tools were hotly requested by the Windows 10 community, so a lot of folks should feel quite happy about what Microsoft has done.

Hyper-V and Enhance Session

In the past, it wasn’t possible for Linux VMs running on Hyper-V to benefit from an enhanced session mode, but this is no longer the case with the Windows 10 v1803 update. Microsoft says this is made possible by the open source XRDP project, which allows the company to interact with Linux VMs in the same way it interacts with Windows via the RDP protocol.

Should you give this a try, you’ll see significant improvements in the user experience, and that’s always good news.

UWP Console Applications

Microsoft is pushing the Universal Windows Platform (UWP) as the future, but despite years of improvements, it’s still limited when compared to the old ways of delivering applications. If you wanted to create a console application, the only option was to work with the legacy options, but now, this is no longer the case.

Yes, you’ve read correctly, UWP Console applications are now supported in Windows. Developers can now ship their Console Applications to the Microsoft Store whenever they please.

Command Line Parameters For Remote Desktop Connections In Windows 11/10

The Remote Desktop Connection (RSD) feature has been active in the Windows operating system since Windows NT Server 4.0; though as a Terminal Server. Come the Windows 10, RSD now exists as an inbuilt standalone app that can be accessed from not only Windows 10 computers but from major mobile and computer OS like Android, iOS, Linux, and Mac. RSD has been used by many companies and firms to control and operate computers in its network remotely. It is also essential for solving problems on devices you can’t access physically.

What is a Remote Desktop Connection?

Remote Desktop Connection (RSD), which is often shortened to Remote Desktop, is a feature created by Microsoft that allows a local computer to control a remote PC after connecting to it over the internet or a network.

Simply put, Remote Desktop Connection is the ability to connect and use another computer from your computer.

Before we proceed, note any edition of Windows can act as a Remote Desktop Client. But to host a remote season, you need a PC running Windows 11/10 Pro or Enterprise.

We have already seen the different ways to enable Remote Desktop Connection in Windows. Today, we will take a look at some command-line options for using RDP. Instead of starting Remote Desktop Connection from the Start menu, Windows 10/8/7 allows you to start it from the search box, from the Run dialog box, or from a command line. With these methods, you can use additional command line parameters to control how Remote Desktop Connection looks or behaves.

Command Line Parameters for Remote Desktop Connections

From the Run dialogue box or the Command Prompt, we can carry so many instructions easily. To see all the possible commands and a brief description you can access, copy and paste any of the commands below:

mstsc.exe /?

This is the syntax-

Continue reading to see a few descriptions:

Whenever you connect to the server, Windows opens a new user session. You can avoid this by opening a connection to the console. Add /console to the mstsc

mstsc /console

To open remote desktop session in full screen, run the command below (/f);

mstsc /f

To specify the remote computer name from the command, use the command below (/v);

mstsc /v:computername

Brief description of the Syntax above

"connection file" – Specifies the name of an .RDP file for the connection.

/admin – Connects you to the session for administering a remote PC.

In this version of Remote Desktop Connection, if the Remote Desktop Session Host role service is installed on the remote computer, running mstsc /admin will do the following (for the current connection only):

Disable Remote Desktop Services client access licensing

Disable time zone redirection

Disable RD Connection Broker redirection

Disable Remote Desktop Easy Print

Disables Plug and Play device redirection for this connection only.

Changes the remote session theme to Windows Classic View (if it’s available) for this connection only.

/f – Starts Remote Desktop in full-screen mode.

/public– Runs Remote Desktop in public mode.

/span – Matches the remote desktop width and height with the local virtual desktop, spanning across multiple monitors, if necessary. To span across monitors, the monitors must be arranged to form a rectangle.

/multimon – Configures the Remote Desktop Services session monitor layout to be identical to the current client-side configuration.

/edit – Opens the specified .RDP connection file for editing.

With the Remote Desktop Connection, you have access to only computers in your network. You can use only one remote desktop connection on Windows at a time, i.e., one remote user per Windows.

However, a PC running Windows 11/10 Server edition can run remote Sessions for different users at the same time.

Read next: How to use Windows Remote Desktop in Windows Home (RDP).

Apropos Linux Command Explained {With Examples}

If you’re someone who frequently uses Linux, you may have come across term ‘apropos’ while using terminal. Apropos is a very useful Linux command that helps users find commands related to a specific topic or keyword. In this article, we will take a closer look at ‘apropos’ command and explain its usage with several examples.

What is Apropos?

‘Apropos’ is a command-line utility in Linux that searches manual pages for a keyword or topic and returns a list of relevant commands. It is a great tool for quickly finding commands you need, especially if you don’t remember exact command name.

The ‘apropos’ command works by searching ‘man’ pages, which are Linux manual pages that contain documentation for various commands, utilities, and system calls. These manual pages are organized by sections, and ‘apropos’ command searches all of sections for specified keyword.

How to use Apropos?

For example, if you want to search for all commands related to “network”, you can type −

apropos network

This will return a list of all commands related to keyword “network”, along with a brief description of each command.

Examples of Apropos Usage

Let’s take a look at some examples of how ‘apropos’ command can be used in different situations.

Example 1: Finding all Commands Related to a Keyword

As mentioned earlier, most common usage of ‘apropos’ command is to find all commands related to a specific keyword or topic. Let’s say you want to find all commands related to “file”. You can type following command −

apropos file

This will return a list of all commands related to “file”, such as ‘cat’, ‘cp’, ‘ls’, ‘mv’, ‘rm’, and many more. list will also include a brief description of each command, making it easier for you to decide which command to use.

Example 2: Finding a Specific Command

Sometimes, you may know name of command you need, but you may not remember its exact syntax or usage. In such a case, you can use ‘apropos’ command to find command you need.

For example, let’s say you want to use ‘grep’ command, but you don’t remember its syntax. You can type following command −

apropos grep

This will return ‘grep’ command along with a brief description of its usage. You can then use ‘man’ command to learn more about ‘grep’ command and how to use it.

Example 3: Finding a Command by Description

In some cases, you may remember description of a command but not its exact name. In such a case, you can use ‘apropos’ command to search for command by its description.

For example, let’s say you remember that there is a command that can be used to find largest file in a directory, but you don’t remember its name. You can type following command −

apropos "largest file"

This will return ‘du’ command, which can be used to find size of a directory or file. You can then use ‘man’ command to learn more about ‘du’ command and how to use it to find largest file in a directory.

Example 4: Finding all Available Options for a Command

Sometimes, you may want to find all available options for a specific command. You can use ‘apropos’ command to search for command and then use ‘man’ command to see all available options.

For example, let’s say you want to find all available options for ‘ls’ command. You can type following command −

apropos ls

This will return ‘ls’ command along with a brief description of its usage. You can then use ‘man’ command to see all available options for ‘ls’ command. To do this, type −

man ls

This will display manual page for ‘ls’ command, which includes a list of all available options along with their descriptions.

Tips for Using Apropos

Here are a few tips for using ‘apropos’ command more effectively −

Be specific with your search terms − ‘apropos’ command will return a lot of results if your search term is too broad. Try to be as specific as possible when searching for commands.

Use quotes for multiple keywords − If you’re searching for commands related to multiple keywords, enclose them in quotes. For example, to search for commands related to both “network” and “security”, you can type: apropos “network security”

Use -a option for more results − By default, ‘apropos’ command only returns first 10 results. If you want to see more results, you can use ‘-a’ option. For example, apropos -a network will return all commands related to “network”.

Use -w option for exact matches − If you want to search for commands that match your search term exactly, use ‘-w’ option. For example, apropos -w grep will only return ‘grep’ command and not other commands that contain word “grep”.

Use -k option for keyword search − If you’re not sure about exact command name but know a keyword that might be used in command, you can use ‘-k’ option. For example, apropos -k “search pattern” will return all commands related to searching for patterns.

Apropos in Shell Scripting

The ‘apropos’ command can also be used in shell scripting. In a shell script, you can use ‘apropos’ command to find command you need and then use it in your script.

For example, let’s say you’re writing a shell script that needs to search for a specific pattern in a file. You can use ‘apropos’ command to find ‘grep’ command and then use it in your script.

#!/bin/bash # Find 'grep' command # Use 'grep' command to search for a pattern in a file $GREP_COMMAND "pattern" file.txt

In this example, ‘apropos’ command is used to find ‘grep’ command, which is then assigned to ‘GREP_COMMAND’ variable. ‘grep’ command is then used to search for a pattern in a file.

Apropos vs. Man

While ‘apropos’ command is a useful tool for finding commands related to a specific topic, it’s important to note that it’s not a replacement for ‘man’ command. ‘man’ command provides detailed documentation for each command, including usage examples, options, and syntax.

The ‘apropos’ command, on other hand, only provides a brief description of each command and its purpose. It’s a useful tool for finding commands, but it doesn’t provide same level of detail as ‘man’ command.

Apropos Alternatives

While ‘apropos’ command is a useful tool for finding commands related to a specific topic, there are some alternative tools you can use as well.

One alternative is ‘whatis’ command, which provides a brief description of a specific command. For example, if you want to know what ‘ls’ command does, you can type −

whatis ls

This will return a brief description of ‘ls’ command, such as “list directory contents”.

Another alternative is ‘man -k’ command, which works in a similar way to ‘apropos’ command. To search for commands related to a specific topic, you can type −

This will return a list of all commands related to specified keyword, along with a brief description of each command.

Apropos in Conjunction with Wildcards

The ‘apropos’ command can also be used in conjunction with wildcards to find commands related to a specific pattern. This can be particularly useful when you want to find all commands related to a certain type of file or operation.

For example, to find all commands related to file compression, you can use following command −

apropos "*compress*"

This will return all commands related to file compression, such as ‘gzip’, ‘bzip2’, ‘zip’, and many others.

Similarly, you can use ‘apropos’ command to find all commands related to a specific type of file. For example, to find all commands related to image files, you can use following command −

apropos "*image*"

This will return all commands related to image files, such as ‘convert’, ‘identify’, ‘mogrify’, and others.

Conclusion

The ‘apropos’ command is a powerful and versatile tool that can help you find commands you need quickly and easily. Whether you’re searching for a specific command, trying to find all available options for a command, or looking for commands related to a specific topic, ‘apropos’ command can help you get job done. So, next time you’re working in Linux terminal and need help finding a command, remember to use ‘apropos’ command!

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