[hackers] [farbfeld] 2ff: Check return values and handle errors || FRIGN

[git]

commit ba154494ae239b9a79fc0947cad497e983c80653
Author:     FRIGN <d...@frign.de>
AuthorDate: Tue Jan 5 16:03:43 2016 +0100
Commit:     FRIGN <d...@frign.de>
CommitDate: Tue Jan 5 16:03:43 2016 +0100

    2ff: Check return values and handle errors
    
    Also, in case convert(1) is not in the path, it will just return an
    error-message giving the MIME-type of the problematic input data.
    The return-value is given properly as well (0 on success, 1 on error).

diff --git a/2ff b/2ff
index 2b0cbd9..19946df 100755
--- a/2ff
+++ b/2ff
@@ -10,9 +10,15 @@ cat > $TMP;
 FORMAT=$(file -ib $TMP | cut -d ";" -f 1);
 
 case "$FORMAT" in
-    image/png)  png2ff < $TMP ;;
-    image/jpeg) jpg2ff < $TMP ;;
-    *) convert $TMP png:- | png2ff ;;
+    image/png)  png2ff < $TMP; ret=$? ;;
+    image/jpeg) jpg2ff < $TMP; ret=$? ;;
+    *) xconvert $TMP png:- 2&>/dev/null | png2ff 2&>/dev/null; ret=$? ;;
 esac
 
 rm $TMP;
+
+if [ $ret -ne 0 ]; then
+       printf "%s: failed to convert %s\n" "$0" "$FORMAT" 1>&2;
+fi
+
+exit $ret;