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I've got this bash one-liner , it runs fine on OSX, but doesn't on Linux, I'm suspecting the linux distro (Busybox) on my Qnap has got something to do with this .

Here is the command that runs on OSX :

find . -type f -name "*.mp4" -exec bash -c 'ffmpeg -i "$0" -c:v copy -c:a libfaac -af "volume=23dB" "fix/$0"' '{}' \;

Now on the Qnap:

find . -type f -name "*.mp4" -exec bash -c 'ffmpeg -i "$0" -c:v copy -c:a libfaac -af "volume=23dB" "fix/$0"' '{}' \;

returns :

BusyBox v1.01 (2015.05.21-17:32+0000) multi-call binary

Usage: find [PATH...] [EXPRESSION]

Search for files in a directory hierarchy. The default PATH is the current directory; default EXPRESSION is '-print'

EXPRESSION may consist of: -follow Dereference symbolic links. -name PATTERN File name (leading directories removed) matches PATTERN. -print Print (default and assumed).

-type X Filetype matches X (where X is one of: f,d,l,b,c,...) -perm PERMS Permissions match any of (+NNN); all of (-NNN); or exactly (NNN) -mtime TIME Modified time is greater than (+N); less than (-N); or exactly (N) days

Like if the find command wasn't working, so if I execute the find command alone :

find . -type f -name "*.mp4"

it works just fine, I get all my files, so I suspect the problem is passing the files to the exec command, and that's where I can't figure it out


bash version osx : GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin14)

bash version linux : GNU bash, version 3.2.57(1)-release (i686-pc-linux-gnu)

  • Why don't you just pipe? In this particular case it's easier to debug if you pipe. – theoden Aug 1 '15 at 23:52
  • BusyBox isn't your typical Linux system (i.e., mostly POSIX with some extensions). Rather, BusyBox is a collection of utilities which lack many features. On the positive side, a script that you can run on BusyBox is likely to run on other systems. The question should be retitled to say "BusyBox". – Thomas Dickey Aug 1 '15 at 23:58
  • Good idea, how would I pipe each file to ffmpeg ? – fingertwist Aug 1 '15 at 23:58
  • @ThomasDickey yeah, that's what I suspect, don't know how to get around it to get my one liner to work on Busybox .. – fingertwist Aug 1 '15 at 23:59
  • I wouldn't try it as a one-liner: making the complicated argument of -exec into a separate script would probably be a good starting point. By keeping the pieces simple, you can pinpoint the limitations to work around one-by-one. – Thomas Dickey Aug 2 '15 at 0:01
2

I suspect it's based on the single/double quote positioning tripping up find.

Typically I always use something like this in a script file (say conv.sh) for more complex operations:

find . -type f -name "*.mp4" | while read FILE
do
  ffmpeg -i "$FILE" -c:v copy -c:a libfaac -af "volume=23dB" "fix/$FILE"
done

Now run this file with debugging:

bash -xv ./conv.sh

A quick and dirty script that should work.

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