Replace ` ` syntax by $( ) in regression test shell scripts.

The latter syntax variant is more readable and easier to nest.

Originally committed as revision 20924 to svn://svn.ffmpeg.org/ffmpeg/trunk

tests/ffserver-regression.sh

@@ -3,7 +3,7 @@
 #perl -e 'chomp($wd = `pwd`); print map { s!tests/data/!!; "<Stream $_>\nFile $wd/tests/data/$_\n</Stream>\n\n" } @ARGV' tests/data/a* >> tests/data/ffserver.conf
 #perl -e 'chomp($wd = `pwd`); print map { s!tests/data/!!; "<Stream $_.asf>\nFile $wd/tests/data/$_\n</Stream>\n\n" } @ARGV' tests/data/a* >> tests/data/ffserver.conf
 
-FILES=`sed -n 's/^[^#]*<Stream \(.*\)>.*/\1/p' $2 | grep -v html`
+FILES=$(sed -n 's/^[^#]*<Stream \(.*\)>.*/\1/p' $2 | grep -v html)
 
 rm -f tests/feed1.ffm
 ./ffserver -d -f "$2" 2> /dev/null &
@@ -15,7 +15,7 @@ sleep 2
     rm -f ff-*;
     WGET_OPTIONS="--user-agent=NSPlayer -q --proxy=off -e verbose=off -e server_response=off"
     for file in $FILES; do
-        if [ `expr $file : "a-*"` != 0 ]; then
+        if [ $(expr $file : "a-*") != 0 ]; then
             wget $WGET_OPTIONS -O - http://localhost:9999/$file > ff-$file
         else
             wget $WGET_OPTIONS -O - http://localhost:9999/$file?date=19700101T000000Z | dd bs=1 count=20000 > ff-$file 2>/dev/null

tests/regression-funcs.sh

@@ -33,9 +33,9 @@ pcm_ref="$datadir/$test_ref.ref.wav"
 crcfile="$datadir/$this.crc"
 target_crcfile="$target_datadir/$this.crc"
 
-if [ X"`echo | md5sum 2> /dev/null`" != X ]; then
+if [ X"$(echo | md5sum 2> /dev/null)" != X ]; then
     do_md5sum() { md5sum -b $1; }
-elif [ X"`echo | md5 2> /dev/null`" != X ]; then
+elif [ X"$(echo | md5 2> /dev/null)" != X ]; then
     do_md5sum() { md5 $1 | sed 's#MD5 (\(.*\)) = \(.*\)#\2 *\1#'; }
 elif [ -x /sbin/md5 ]; then
     do_md5sum() { /sbin/md5 -r $1 | sed 's# \**\./# *./#'; }
@@ -60,8 +60,8 @@ do_ffmpeg()
     else
         wc -c $f >> $logfile
     fi
-    expr "`cat $bench`" : '.*utime=\(.*s\)' > $bench2
-    echo `cat $bench2` $f >> $benchfile
+    expr "$(cat $bench)" : '.*utime=\(.*s\)' > $bench2
+    echo $(cat $bench2) $f >> $benchfile
 }
 
 do_ffmpeg_nomd5()
@@ -78,8 +78,8 @@ do_ffmpeg_nomd5()
     else
         wc -c $f >> $logfile
     fi
-    expr "`cat $bench`" : '.*utime=\(.*s\)' > $bench2
-    echo `cat $bench2` $f >> $benchfile
+    expr "$(cat $bench)" : '.*utime=\(.*s\)' > $bench2
+    echo $(cat $bench2) $f >> $benchfile
 }
 
 do_ffmpeg_crc()
@@ -88,7 +88,7 @@ do_ffmpeg_crc()
     shift
     echo $ffmpeg $FFMPEG_OPTS $* -f crc "$target_crcfile"
     $ffmpeg $FFMPEG_OPTS $* -f crc "$target_crcfile"
-    echo "$f `cat $crcfile`" >> $logfile
+    echo "$f $(cat $crcfile)" >> $logfile
     rm -f "$crcfile"
 }
 
@@ -98,8 +98,8 @@ do_ffmpeg_nocheck()
     shift
     echo $ffmpeg $FFMPEG_OPTS $*
     $ffmpeg $FFMPEG_OPTS -benchmark $* > $bench
-    expr "`cat $bench`" : '.*utime=\(.*s\)' > $bench2
-    echo `cat $bench2` $f >> $benchfile
+    expr "$(cat $bench)" : '.*utime=\(.*s\)' > $bench2
+    echo $(cat $bench2) $f >> $benchfile
 }
 
 do_video_decoding()

tests/seek-regression.sh

@@ -11,7 +11,7 @@ datadir="tests/data"
 logfile="$datadir/seek.regression"
 reffile="$1"
 
-list=`grep '^tests/data/[ab]-' "$reffile"`
+list=$(grep '^tests/data/[ab]-' "$reffile")
 rm -f $logfile
 for i in $list ; do
     echo ---------------- >> $logfile