Bash: Difference between revisions
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The following is a list of the most common built in commands in bash with examples: | The following is a list of the most common built in commands in bash with examples: | ||
*alias | *alias | ||
**<code>alias dir=ls</code> | **<code>alias dir=ls</code> | ||
**Will create a special note that says "hey, if this command is executed, run this command instead." The example will basically say if the command dir is typed, run ls instead. | **Will create a special note that says "hey, if this command is executed, run this command instead." The example will basically say if the command dir is typed, run ls instead. | ||
*echo | |||
**<code>echo "bash"</code> | |||
**<code>echo "$PATH"</code> | |||
**Prints out the text passed as an argument. Can be used in conjunction with variables to view them. | |||
*cd | |||
**<code>cd Desktop</code> | |||
**Changes the working directory. | |||
*export | |||
**<code>export MYVAR="PASSME"</code> | |||
**Sets variables to be passed to child processes of the shell itself. | |||
*history | |||
**<code>history</code> | |||
**<code>history -c</code> | |||
**Shows history of commands ran, use -c to clear it. | |||
*source | |||
**<code>source .bashrc</code> | |||
**Restarts the shell using the file specified as the file that contains all the options. By default this is a file in your home directory named ".bashrc" and sourcing it again will restart the shell if you add anything to the file (like aliases). | |||
*pwd | |||
**prints the current directory. | |||
*exit/logout | |||
**The logout command only works if you are not running a terminal in a Linux UI. This does exactly what it sounds like and logs you out. The exit command does the same, but it works regardless of if you are running a terminal in the UI or running Linux with just a command line. |
Latest revision as of 18:35, 21 March 2024
Bash (short for Bourne Again SHell) is the main scripting language used to provide a command line to Linux. I covered it briefly in Linux 101, but I will be covering it more in depth here. Very rarely will you write entire programs in bash, but it is a quick way to do many tasks all in one if you master it, it's just a little confusing as most lower level languages tend to be at times.
The most basic thing with bash, is that there is a variable that sets what directories to look for executable files. Every time you run a command, it searches these folders for a matching file to execute. These files can be anything, from python scripts to bash scripts to compiled executable files.
Bash builtins
The following is a list of the most common built in commands in bash with examples:
- alias
alias dir=ls
- Will create a special note that says "hey, if this command is executed, run this command instead." The example will basically say if the command dir is typed, run ls instead.
- echo
echo "bash"
echo "$PATH"
- Prints out the text passed as an argument. Can be used in conjunction with variables to view them.
- cd
cd Desktop
- Changes the working directory.
- export
export MYVAR="PASSME"
- Sets variables to be passed to child processes of the shell itself.
- history
history
history -c
- Shows history of commands ran, use -c to clear it.
- source
source .bashrc
- Restarts the shell using the file specified as the file that contains all the options. By default this is a file in your home directory named ".bashrc" and sourcing it again will restart the shell if you add anything to the file (like aliases).
- pwd
- prints the current directory.
- exit/logout
- The logout command only works if you are not running a terminal in a Linux UI. This does exactly what it sounds like and logs you out. The exit command does the same, but it works regardless of if you are running a terminal in the UI or running Linux with just a command line.