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Shell Scripting

Last modified: 2023-11-03

For Loop

#!/bin/bash
for i in {1..5}
do
    echo "Hello $i"
done

4 Digits Loop

#!/bin/bash
for i in {0000..9999}
do
    echo $i
done

Read Text Line by Line

read-text.sh

#!/bin/bash
while read line
do
    echo $line
done < example.txt

Retrieve Arguments

Getopts is useful.
Create "my_opt.sh".

#!/bin/bash

getopts c cmd
echo $cmd

Run. This output is the current username.

./my_opt.sh -cwhoami

  • While Loop and Retrieving Arguments

    Create “my_while_opt.sh”.

```sh
while getopts ab: flag
do
    case "${flag}" in
        a) command1=${OPTARG};;
        b) command2=${OPTARG};;
    esac
done

cmd1=$($command1)
echo $cmd1
cmd2=$($command2)
echo $cmd2

    Run. This output is the current username and current time.

    ./my_while_opt.sh -awhoami -btime
# kali
# real  1111.11s ...