Question

Suppose I have this simple script

#! /bin/sh

if [ $# -ne 2 ]
then
        echo "Usage: $0 arg1 arg2"
        exit 1
fi

head $1 $2

## But this is supposed to be:
## if -f flag is set, 
##      call [tail $1 $2]
## else if the flag is not set
##      call [head $1 $2]

So what’s the simplest way to add a ‘flag’ checking to my script?

Thanks

Answer 1

fflag=no
for arg in "$@"
do
    test "$arg" = -f && fflag=yes
done

if test "$fflag" = yes
then
    tail "$1" "$2"
else
    head "$1" "$2"
fi

This simpler approach might also be viable:

prog=head
for i in "$@"
do
    test "$i" = -f && prog=tail
done

$prog "$1" "$2"