use portable "command -v" to detect installed programs, part 3

The "which" utility is not guaranteed to be installed either, and if it
is, its behavior is not portable either. This means that when various
programs are installed, the `which` check will report a fatal error
because the which tool did not exist and the shell returned a nonzero
status when attempting to fork+exec. If it did exist, it might not be an
implementation of `which` that returns nonzero when commands do not
exist.

The general scripting suggestion is to use the "command -v" shell
builtin; this is required to exist in all POSIX 2008 compliant shells,
and is thus guaranteed to work everywhere.

For some in-depth discussions on the topic, see:
- https://mywiki.wooledge.org/BashFAQ/081
- https://unix.stackexchange.com/questions/85249/why-not-use-which-what-to-use-then/85250#85250

Examples of open-source shells likely to be installed as /bin/sh on
Linux, which implement the 15-year-old standard: ash, bash, busybox,
dash, ksh, mksh and zsh.

This commit updates packaging recipes.

Change-Id: I934863f6c8e05728e85278568899f581d749e0ea
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/160664
Tested-by: Ilmari Lauhakangas <ilmari.lauhakangas@libreoffice.org>
Reviewed-by: Ilmari Lauhakangas <ilmari.lauhakangas@libreoffice.org>

3 files changed, 11 insertions, 11 deletions

diff --git a/sysui/desktop/debian/postinst b/sysui/desktop/debian/postinst
index f3220f311fdf..e07ad7fa0649 100755
--- a/sysui/desktop/debian/postinst
+++ b/sysui/desktop/debian/postinst
@@ -34,7 +34,7 @@ if [ "$1" = "configure" ] ; then  # first install
   if [ -e /usr/share/icons/hicolor/icon-theme.cache ] ; then
     # touch it, just in case we cannot find the binary...
     touch /usr/share/icons/hicolor
-    if (which gtk-update-icon-cache); then
+    if command -v gtk-update-icon-cache; then
       gtk-update-icon-cache /usr/share/icons/hicolor
     fi
     # ignore errors (e.g. when there is a cache, but no index.theme)
diff --git a/sysui/desktop/debian/postrm b/sysui/desktop/debian/postrm
index 0e6099ea5b43..2e53e6062352 100755
--- a/sysui/desktop/debian/postrm
+++ b/sysui/desktop/debian/postrm
@@ -14,7 +14,7 @@ if [ "$1" != "purge" ]; then
   if [ -e /usr/share/icons/hicolor/icon-theme.cache ] ; then
     # touch it, just in case we cannot find the binary...
     touch /usr/share/icons/hicolor
-    if (which gtk-update-icon-cache); then
+    if command -v gtk-update-icon-cache; then
       gtk-update-icon-cache /usr/share/icons/hicolor
     fi
     # ignore errors (e.g. when there is a cache, but no index.theme)
diff --git a/sysui/desktop/freedesktop/freedesktop-menus.spec b/sysui/desktop/freedesktop/freedesktop-menus.spec
index 203d1a881bd3..ff083d71fe9c 100644
--- a/sysui/desktop/freedesktop/freedesktop-menus.spec
+++ b/sysui/desktop/freedesktop/freedesktop-menus.spec
@@ -86,7 +86,7 @@ rm -rf $RPM_BUILD_ROOT
 
 if [ -x /opt/gnome/bin/update-desktop-database ]; then
     /opt/gnome/bin/update-desktop-database -q
-elif (which update-desktop-database); then
+elif command -v update-desktop-database; then
   update-desktop-database -q /usr/share/applications
 fi
 
@@ -99,7 +99,7 @@ if [ "$2" = "0" ] ; then
   # the triggering package gets removed
   if [ -x /opt/gnome/bin/update-desktop-database ]; then
       /opt/gnome/bin/update-desktop-database -q
-  elif (which update-desktop-database); then
+  elif command -v update-desktop-database; then
     update-desktop-database -q /usr/share/applications
   fi
 fi
@@ -111,11 +111,11 @@ fi
 if [ "$1" = "1" ] ; then  # first install
   if [ -x /opt/gnome/bin/update-desktop-database ]; then
     /opt/gnome/bin/update-desktop-database -q
-  elif (which update-desktop-database); then
+  elif command -v update-desktop-database; then
     update-desktop-database -q /usr/share/applications
   fi
 
-  if (which update-mime-database); then
+  if command -v update-mime-database; then
     update-mime-database /usr/share/mime
   fi
 fi
@@ -165,7 +165,7 @@ if [ -e /usr/share/icons/hicolor/icon-theme.cache ] ; then
     touch /usr/share/icons/hicolor
     if [ -x /opt/gnome/bin/gtk-update-icon-cache ]; then
         /opt/gnome/bin/gtk-update-icon-cache -q /usr/share/icons/hicolor
-    elif (which gtk-update-icon-cache); then
+    elif command -v gtk-update-icon-cache; then
         gtk-update-icon-cache -q /usr/share/icons/hicolor
     fi
     # ignore errors (e.g. when there is a cache, but no index.theme)
@@ -329,7 +329,7 @@ fi
 
 if [ -x /opt/gnome/bin/update-desktop-database ]; then
     /opt/gnome/bin/update-desktop-database -q
-elif (which update-desktop-database); then
+elif command -v update-desktop-database; then
   update-desktop-database -q /usr/share/applications
 fi
 
@@ -348,11 +348,11 @@ fi
 if [ "$1" = 0 ] ; then # only run when erasing the package - other cases handled by the triggers
   if [ -x /opt/gnome/bin/update-desktop-database ]; then
     /opt/gnome/bin/update-desktop-database -q
-  elif (which update-desktop-database); then
+  elif command -v update-desktop-database; then
     update-desktop-database -q
   fi
 # run always - both when upgrading as well as when erasing the package
-  if (which update-mime-database); then
+  if command -v update-mime-database; then
     update-mime-database /usr/share/mime
   fi
 fi
@@ -363,7 +363,7 @@ if [ -e /usr/share/icons/hicolor/icon-theme.cache ] ; then
   touch /usr/share/icons/hicolor
   if [ -x /opt/gnome/bin/gtk-update-icon-cache ]; then
     /opt/gnome/bin/gtk-update-icon-cache -q /usr/share/icons/hicolor
-  elif (which gtk-update-icon-cache); then
+  elif command -v gtk-update-icon-cache; then
     gtk-update-icon-cache -q /usr/share/icons/hicolor
   fi
   # ignore errors (e.g. when there is a cache, but no index.theme)