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command line arguments in bash script

To input arguments into a bash script, like any normal command line program, there are special variables set aside for this

The arguments are stored in variables with a number in the order of the argument starting at 1
  • First Argument: $1
  • Second Argument: $2
  • Third Argument: $3
  • Example
    • command: ./script.sh alpha beta gamma
    • Variables: $1=='alpha'; $2=='beta'; $3=='gamma'

The variable $0 is the script's name.  
The total number of arguments is stored in $#. 
The variables $@ and $* return all the arguments.

Script Example
#!/bin/bash
echo "the $1 eats a $2 every time there is a $3"
echo "bye:-)"
  • Command: ./script.sh dog bone moose
  • Output:
    the dog eats a bone every time there is a moose
    bye:-)

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