Bash (Unix shell): Difference between revisions
(→Usage) |
|||
Line 44: | Line 44: | ||
<syntaxhighlight lang="bash"> | <syntaxhighlight lang="bash"> | ||
PS1='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$' | PS1='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$' | ||
</syntaxhighlight> | |||
==Brace Expansion== | |||
When you type the following: | |||
<syntaxhighlight lang="bash"> | |||
echo {red,green,blue}_apple | |||
</syntaxhighlight> | |||
bash will print out | |||
<pre> | |||
red_apple green_apple blue_apple | |||
</pre> | |||
If you want to save this into a variable, you can save it as an array: | |||
<syntaxhighlight> | |||
APPLES=({red,green,blue}_apple) | |||
echo "${APPLES[@]}" | |||
</syntaxhighlight> | </syntaxhighlight> |
Revision as of 12:07, 1 July 2020
Bash Scripting
Getting Started
Here is an example bash script
#!/bin/bash
# A simple variable example
myvariable=Hello
anothervar=Fred
echo $myvariable $anothervar
You can check your bash scripts using https://www.shellcheck.net/.
Usage
Basic If Statements
https://linuxize.com/post/bash-if-else-statement/
if [[ $VAR -gt 10 ]] then
echo "The variable is greater than 10."
elif [[ $VAR -eq 10 ]] then
echo "The variable is equal to 10."
else
echo "The variable is less than 10."
fi
Comparisons
-eq
is==
-gt
is>
-ge
is>=
Check if File/Folder Exists
See https://linuxize.com/post/bash-check-if-file-exists/#check-if-directory-exist.
.bashrc
Your .bashrc
file will be loaded for each terminal.
Presentation of Shell Variable
Add the following to show your
PS1='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$'
Brace Expansion
When you type the following:
echo {red,green,blue}_apple
bash will print out
red_apple green_apple blue_apple
If you want to save this into a variable, you can save it as an array:
APPLES=({red,green,blue}_apple)
echo "${APPLES[@]}"