Jeffrey Walton via Gnupg-devel wrote in
<CAH8yC8ndjkepDfetji2efbdA1m0khiuWWoTfjv5ng7Eb7Vc-KQ@mail.gmail.com>:
|On Mon, Aug 15, 2022 at 4:04 PM Sam James via Gnupg-devel
|<gnupg-devel@lists.gnupg.org> wrote:
|>
|> `which` is an external command which isn't required by POSIX.
|>
|> Debian and other distributions (like Gentoo!) are looking
|> to drop it from their base set of packages.
|>
|> Switch to `command -v` which should always work instead.
|>
|> Note we already use `command -v` at the start of this test anyway.
|
|+1. `command -v` is Posix, and it properly handles things like user
|environments and shell aliases.
It is not that easy. You possibly want to use Robert Elz's
find_command script (don't mind my name):
#!/bin/sh -
#@ Find an executable command within a POSIX shell.
#@ which(1) is not standardized, and command(1) -v may return non-executable,
#@ so here is how it is possible to really find a usable executable file.
#@ Use like this:
#@ thecmd_testandset chown chown ||
#@ PATH="/sbin:${PATH}" thecmd_set chown chown ||
#@ PATH="/usr/sbin:${PATH}" thecmd_set_fail chown chown
#@ or
#@ thecmd_testandset_fail MAKE make
#@ or
#@ MAKE=/usr/bin/make thecmd_testandset_fail MAKE make
#@ _However_, in order to support prefilled variables like "awk='busybox awk'"
#@ spaces in command names found via path search are not supported.
#@ That is to say that we take user-prefilled variable names with spaces as
#@ granted, and actively fail to find commands with spaces ourselfs; like this
#@ users of these functions can simply say: $VAR args, not "$VAR" args.
#
# 2017 - 2022 Steffen Nurpmeso <steffen@sdaoden.eu>.
# Thanks to Robert Elz (kre).
# Public Domain
## First of all, the actual functions need some environment:
if [ -z "${SU_FIND_COMMAND_INCLUSION}" ]; then
VERBOSE=1
( set -o noglob ) >/dev/null 2>&1 && noglob_shell=1 || unset noglob_shell
msg() {
fmt=${1}
shift
printf >&2 -- "${fmt}\n" "${@}"
}
fi
## The actual functions
acmd_test() { fc__acmd "${1}" 1 0 0; }
acmd_test_fail() { fc__acmd "${1}" 1 1 0; }
acmd_set() { fc__acmd "${2}" 0 0 0 "${1}"; }
acmd_set_fail() { fc__acmd "${2}" 0 1 0 "${1}"; }
acmd_testandset() { fc__acmd "${2}" 1 0 0 "${1}"; }
acmd_testandset_fail() { fc__acmd "${2}" 1 1 0 "${1}"; }
thecmd_set() { fc__acmd "${2}" 0 0 1 "${1}"; }
thecmd_set_fail() { fc__acmd "${2}" 0 1 1 "${1}"; }
thecmd_testandset() { fc__acmd "${2}" 1 0 1 "${1}"; }
thecmd_testandset_fail() { fc__acmd "${2}" 1 1 1 "${1}"; }
## -- >8 - - 8< -- ##
fc__pathsrch() { # pname=$1 exec=$2 varname=$3 verbok=$4
fcps__pname=$1 fcps__exec=$2 fcps__varname=$3 fcps__verbok=$4
# Commands with spaces are not found
if [ "${fcps__exec}" != "${fcps__exec#* }" ]; then
[ -n "${VERBOSE}" ] && [ ${fcps__verbok} -ne 0 ] &&
msg ' . ${%s} ... %s (has spaces, CANNOT be found)' \
"${fcps__pname}" "${fcps__exec}"
return 1
fi
# It may be an absolute path, check that first
if [ "${fcps__exec}" != "${fcps__exec#/}" ] &&
[ -f "${fcps__exec}" ] && [ -x "${fcps__exec}" ]; then
[ -n "${VERBOSE}" ] && [ ${fcps__verbok} -ne 0 ] &&
msg ' . ${%s} ... %s' \
"${fcps__pname}" "${fcps__exec}"
[ -n "${fcps__varname}" ] &&
eval "${fcps__varname}"="${fcps__exec}"
return 0
fi
# Manual search over $PATH
fcps__oifs=${IFS} IFS=:
[ -n "${noglob_shell}" ] && set -o noglob
set -- ${PATH}
[ -n "${noglob_shell}" ] && set +o noglob
IFS=${fcps__oifs}
for fcps__path
do
if [ -z "${fcps__path}" ] || [ "${fcps__path}" = . ]; then
if [ -d "${PWD}" ]; then
fcps__path=${PWD}
else
fcps__path=.
fi
fi
if [ -f "${fcps__path}/${fcps__exec}" ] &&
[ -x "${fcps__path}/${fcps__exec}" ]; then
[ -n "${VERBOSE}" ] && [ ${fcps__verbok} -ne 0 ] &&
msg ' . ${%s} ... %s' \
"${fcps__pname}" "${fcps__path}/${fcps__exec}"
[ -n "${fcps__varname}" ] &&
eval "${fcps__varname}"="${fcps__path}/${fcps__exec}"
return 0
fi
done
return 1
}
fc__acmd() {
fca__pname=${1} fca__dotest=${2} fca__dofail=${3} \
fca__verbok=${4} fca__varname=${5}
# Is the variable prefilled?
if [ "${fca__dotest}" -ne 0 ]; then
eval fca__dotest=\$${fca__varname}
if [ -n "${fca__dotest}" ]; then
# It could be something like "busybox awk". So if there is any
# whitespace in a given variable, this cannot truly be solved in an
# automatic fashion, we need to take it for granted
if [ "${fca__dotest}" = "${fca__dotest#* }" ] ||
[ -f "${fca__dotest}" ]; then :; else
[ -n "${VERBOSE}" ] && [ ${fca__verbok} -ne 0 ] &&
msg ' . ${%s} ... %s (spacy user data, unverifiable)' \
"${fca__pname}" "${fca__dotest}"
return 0
fi
if fc__pathsrch "${fca__pname}" "${fca__dotest}" "${fca__varname}" \
${fca__verbok}; then
return 0
fi
msg 'WARN: ignoring non-executable ${%s}=%s' \
"${fca__pname}" "${fca__dotest}"
fi
fi
if fc__pathsrch "${fca__pname}" "${fca__pname}" "${fca__varname}" \
${fca__verbok}; then
return 0
fi
[ -n "${fca__varname}" ] && eval "${fca__varname}"=
[ ${fca__dofail} -eq 0 ] && return 1
msg 'ERROR: no trace of utility '"${fca__pname}"
exit 1
}
# s-sh-mode
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
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