Wednesday, May 12, 2010

Linux Commands Tutorials - Using the Ls Command With Examples of Options - A Hands-On Tutorial Help

This Linux command tutorial shows you a lot of examples of how to run the Linux ls command using popular, commonly used command options.

All of the Linux command examples shown below have been designed to work with all Linux distributions (versions).

So, if you run all of the Linux commands shown below yourself, you'll have a mini Linux command tutorial.


Try it - it is a great manner to get Linux training!

The Linux ls Command

The Linux ls (list) command is a very popular Linux command that is used to show a listing of directories and files.

Linux ls Command Tutorial - Showing Examples of Using ls Command Options

Run the CD (alteration directory) command below to alteration into the etc directory (folder) so we have lots of directories and files for the ls command examples below.

]$ CD /etc

Run the ls command without any options.

]$ ls

This shows a listing of all directories and files (items) in the current directory, which is the etc directory. There are several items and only the end of the listing appears. you are able to't see the top of the listing because it has scrolled off the screen.

So, we will use the | (vertical bar - above the Enter key on a lot of keyboards) to "pipe" the output of the ls command to the less command - and so see some options of the ls command.



Linux Tips: To type the | (vertical bar) on most keyboards, hold down the shift key and press the (backslash) key.



Linux Tips: The less command is used to pause the output of a command after the first "screenful", so the output does not scroll off the screen. The less command is a Linux command, and not an option of the ls command.

]$ ls | less

Now, because you piped the output of the ls command to the less command, you are able to use the Up Arrow, Down Arrow and Page Up and Page Down keys to scroll through the output of the ls command.

Press the Down Arrow key a couple of times; then the Up Arrow key and so Page Up and Page Down. A nice manner to view the files in the Linux file system!

Notice that just the item (directory and file) names appear. You do not see any other information, such as the size and date.

Press the letter "q" (without the quotes) to quit out of the less command. Do this after running a piece of the command examples below.

Now run the ls command with the -l (for long) option to get a "long" and more detailed listing of the items in the etc directory.

]$ ls -l | less

Now you get lots more info on each item! The size (in bytes) of the item appears at the left of the date. When a "d" appears at the far left of an item, this indicates that the item is a directory (folder).

Try scrolling down and so scrolling up.

The ls command below applies both the -l and -S options. The -S option causes the items to be sorted by size, with the largest item at the top.



Linux Tips: Linux commands are case sensitive, so when you see an upper case "S", be sure to type in a capital "S" (without the quotes).

]$ ls -lS | less

Press the Page Down key until you get to the bottom of the listing.

A Practical Linux ls Command Example - Listing Linux Text Configuration Files

Now let's say you need to consider some of the system configuration settings in a Linux text file. You know the file is in the current directory (etc) and that the file ends in ".conf", but you are able to't remember the full name of the file.

To see all possible file names, you use a Linux "pattern" of "*.conf" . This pattern applies the * (asterisk) wildcard character to show all files that end in ".conf".

]$ ls -l *.conf | less

Now you see the Linux text file you need and can check out the settings in it.

Quit out of the less command.

The exit command is used to close a terminal emulation window and end a Linux bash shell "session".

]$ exit



Beyond This "Linux Commands Tutorials" Article

The Linux ls command is among the most popular and commonly used Linux commands. There are lots of applies for the ls command and a lot of other useful ls command options.

As part of your Linux training, you also need to learn how to use the ls command to: get a listing of "hidden" files, get a listing using an absolute path and relative path, get listings using a lot of different "patterns" (with wildcard characters), and list directories and files recursively.

Now, imagine watching a clearly narrated Linux video tutorial that not only shows all of the examples above, but also shows you the full output of each command - you get to learn Linux live!

Then imagine pausing the Linux video after each example and trying the commands yourself - an excellent manner to get Linux training!

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