Command line arguments in Bash

bash command-line-arguments
Pascal picture Pascal · Aug 20, 2012 · Viewed 64.1k times · Source

I want to write a bash script which takes different arguments. It should be used like normal linux console programs:

my_bash_script -p 2 -l 5 -t 20

So the value 2 should be saved in a variable called pages and the parameter l should be saved in a variable called length and the value 20 should be saved in a variable time.

What is the best way to do this?

Answer

Theodros Zelleke picture Theodros Zelleke · Aug 20, 2012

Use the getopts builtin:
here's a tutorial

pages=  length=  time=

while getopts p:l:t: opt; do
  case $opt in
  p)
      pages=$OPTARG
      ;;
  l)
      length=$OPTARG
      ;;
  t)
      time=$OPTARG
      ;;
  esac
done

shift $((OPTIND - 1))

shift $((OPTIND - 1)) shifts the command line parameters so that you can access possible arguments to your script, i.e. $1, $2, ...

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