| echo $0 | display current shell |
| cat /etc/shells | display available shells |
| cat /etc/passwd | shows user's shell e.g. /bin/bash) |
| chmod a+x scriptname | allow execute permission for all |
| ./script.bash | execute from current location |
| /home/userdir/script.bash | execute from absolute location |
| \#!/bin/bash | Shell |
| \# This script does X | Comment |
| echo/cp/grep | Command |
| if/while/for | Statement |
| \#!/bin/bash \# made by Nicolas Sotelo whoami echo pwd echo hostname echo ls -ltr echo | shell comment command space |
| \#!/bin/bash a=Nicolas b=Sotelo c="Linux Class" echo "My first name is $a" echo "My surname is $b" echo "My class is $c" | set variable echo variable |
| \#!/bin/bash echo Hello, my name is Nicolas Sotelo echo echo What is your name? read namevar echo echo Hello $namevar echo | read sets variable to the user's input echo variable |
| \#!/bin/bash hnvar=`hostname` echo Hello, my hostname is $hnvar echo echo What is your name? read namevar echo echo Hello $namevar echo | set variable as a `command` echo the output |
| \#!/bin/bash count=100 if \[ $count -eq 100 \] then echo Count is 100 else echo Count is not 100 fi | end if statement |
| \#!/bin/bash clear if \[ -e /home/nsotelo/error.txt \] then echo "File exists" else echo "File does not exist" fi | |
| \#!/bin/bash clear echo echo "What is your name?" echo read namevar echo echo Hello $namevar sir echo echo "Do you like working in IT? (y/n)" read Like echo if \[ "$Like" == "y" \] then echo "You are cool" elif \[ "$Like" == "n" \] then echo "You should try IT, it's a good field" echo fi |
| \#!/bin/bash for numv in 1 2 3 4 5 do echo "Welcome $numv times" done | assign 1 2 3 4 5 to numv repeatedly display for each of the specified variables |
| \#!/bin/bash for actionv in eat run jump play do echo "See Nick $actionv" done | assign eat run jump play to actionv repeatedly display for each of the specified variables |
| \#!/bin/bash for filev in {1..5} do touch $filev done | for loop to create 5 files named 1-5 |
| \#!/bin/bash for filev in {1..5} do rm $filev done | for loop to delete 5 files named 1-5 |
| \#!/bin/bash i=1 for day in Mon Tue Wed Thu Fri do echo "Weekday $((i++)): $day" done | specify days in for loop |
| \#!/bin/bash a=1 for username in `awk -F: '{print $1}' /etc/passwd` do echo "Username $((a++)) : $username" done | list all users one by one from /etc/passwd file |