examples/functions/whatis

#
# whatis -- and implementation of the 10th Edition Unix sh builtin `whatis'
#	    command.
#
# usage: whatis arg [...]
#
# For each argument, whatis prints the associated value as a parameter,
# builtin, function, alias, or executable file as appropriate.  In each
# case, the value is printed in a form which would yield the same value
# if typed as input to the shell itself.
#
#
#  Chet Ramey <chet.ramey@case.edu>
#
#  Copyright 1994 Chester Ramey
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2, or (at your option)
#   any later version.
#
#   TThis program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software Foundation,
#   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.


whatis()
{
	local wusage='usage: whatis arg [arg...]'
	local fail=0

	if [ $# -eq 0 ] ; then
		echo "$wusage"
		return 1
	fi

	for arg
	do
		case $(builtin type -type $arg 2>/dev/null) in
		"alias")
			builtin alias "$arg"
			;;
		"function")
			builtin type "$arg" | sed 1d
			;;
		"builtin")
			echo builtin "$arg"
			;;
		"file")
			builtin type -path "$arg"
			;;
		*)
			# OK, we could have a variable, or we could have nada
			if [ "$(eval echo \${$arg+set})" = "set" ] ; then
				# It is a variable, and it is set
				echo -n "$arg="
				eval echo '\"'\$$arg'\"'
			else
				echo whatis: $arg: not found
				fail=1
			fi
			;;
		esac
	done
	return $fail
}