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#!/bin/bash
name="whichhead"
version="1.1"
read -r -d '' help_message <<-EOF
Print the first 10 lines from a program
Usage: whichhead [OPTIONS] [PROGRAM ..]
Options:
-h, --help print this message and exit
-n N, --number N print the first N lines (Default: 10)
-q, --quiet suppress error messages
-v, --verbose show additional messages
-V, --version print version number and exit
EOF
source /usr/local/lib/mylib.bash
positional=()
num_lines=10
quiet=0
verbose=0
while [[ $# -gt 0 ]]; do
case $1 in
-h|--help)
help_msg
shift
;;
-n|--number)
if ! is_natural "$2"; then
error_msg "Cannot set number of lines to '${2}' (not an integer >= 0)"
fi
debug_msg "Setting number of lines to ${2} (was ${num_lines})"
num_lines="$2"
shift; shift
;;
-q|--quiet)
debug_msg "Setting quiet option to 1 (was ${quiet})"
quiet=1
shift
;;
-v|--verbose)
debug_msg "Setting verbose option to 1 (was ${verbose})"
verbose=1
shift
;;
-V|--version)
version_msg
;;
*)
debug_msg "Argument '${1}' added to positional array"
positional+=("$1")
shift
;;
esac
done
# main routine
code=0
for target in "${positional[@]}"; do
abs_target=$(command -v "$target")
if [[ -z $abs_target ]]; then
nonfatal_error_msg "No such program '${target}'"
code=1
else
/usr/bin/head "$abs_target" -n "$num_lines"
fi
done
# return stored code
exit "$code"