Prints out every in between the first two arguments

inbetween

#!/bin/sh
#
# Prints out every in between the first two arguments:
#
# Example:
# 
# % inbetween '- - \[' '\]'   # Dates from an apache log file
#
fst=$1; shift
if [[ x$fst = 'x' ]]; then
    echo "First delimiter required"
    exit 1
fi

snd=$1; shift
if [[ x$snd = 'x' ]]; then
    echo "Second delimiter required"
    exit 1
fi

sed -e "s/.*$fst//g"  -e "s/$snd.*//g"