Do not depend on readlink(1) or -q

Solaris 10 lacks readlink(1). Additionally, its different grep(1) and
diff(1) do not take a `-q` flag.

Use a Perl one-liner instead of readlink(1) which is missing on Solaris 10.
Also because /usr/bin/grep and diff(1) don't understand the `-q` option, make
them go quiet by redirecting stdout to `/dev/null` instead.

The Perl dependency only exists in the test suite, so it does not incur
a runtime penalty for end users.

This is to work around the fact that readlink(1) is missing on Solaris.
The tradeoff is: on Solaris, installing third-party software (readlink)
is a pain, whereas on e.g. FreeBSD installing third-party software
(Perl) is simple and common.

2 files changed, 4 insertions, 4 deletions

diff --git a/bin/lsrc.in b/bin/lsrc.in
index 47ae889..fcf5fbe 100755
--- a/bin/lsrc.in
+++ b/bin/lsrc.in
@@ -118,7 +118,7 @@ show_file() {
     output="$output:$sigil"
   fi
 
-  if echo "$DEST_STACK:" | grep -vq ":$dest_file:"; then
+  if echo "$DEST_STACK:" | grep -v ":$dest_file:" >/dev/null; then
     DEST_STACK="$DEST_STACK:$dest_file"
     $PRINT "$output"
   else
@@ -167,7 +167,7 @@ dotfiles_dir_excludes() {
   $DEBUG "  with excludes: $excludes"
 
   for exclude in $excludes; do
-    if echo "$exclude" | grep -q ':'; then
+    if echo "$exclude" | grep ':' >/dev/null; then
       dotfiles_dir_pat="$(echo "$exclude" | sed 's/:.*//')"
       file_glob="$(echo "$exclude" | sed 's/.*://')"
 
diff --git a/bin/rcup.in b/bin/rcup.in
index f818258..bdae664 100755
--- a/bin/rcup.in
+++ b/bin/rcup.in
@@ -123,11 +123,11 @@ replace_file() {
 }
 
 is_nested() {
-  echo "$1" | sed "s:$DEST_DIR/::" | grep -q '/'
+  echo "$1" | sed "s:$DEST_DIR/::" | grep '/' >/dev/null
 }
 
 is_identical() {
-  diff -q -s "$1" "$2" > /dev/null
+  diff -c "$1" "$2" > /dev/null 2>&1
 }
 
 handle_dir() {