bash command substitution

Vukovics Mihaly vm@informatik.hu
Sun Oct 1 06:40:00 GMT 2017


Hello All,


I just wanted to use my bash script written in Debian 8 in 
cygwin(latest, win10 64bit), but does not work.
At a specific line there is a command substitution trying to get result 
from ffprobe:

VHEIGHT=$(ffprobe -v error -show_entries stream=width,height -of 
default=noprint_wrappers=1 ${OLDFILE} | grep "height" | cut -f2 -d'=')

For debugging purpose the same command is executed without putting the 
result into a variable, and works! Does anyone know why is it not 
working in cygwin?

Code:

...
declare -i VHEIGHT
ffprobe -v error -show_entries stream=width,height -of 
default=noprint_wrappers=1 ${OLDFILE} | grep height | cut -f2 -d'='
VHEIGHT=$(ffprobe -v error -show_entries stream=width,height -of 
default=noprint_wrappers=1 ${OLDFILE} | grep "height" | cut -f2 -d'=')
...

Here is some debug log (set -x):

....
+ declare -i VHEIGHT
+ ffprobe -v error -show_entries stream=width,height -of 
default=noprint_wrappers=1 P1220312.MP4
+ grep height
+ cut -f2 -d=
2160              # this woudl be the desired value
+ VHEIGHT=        # here the variable is empty!
+ VIDSTABDETECTOPTS=:shakiness=10
+ VIDSTABDETECTOPTS+=:result=P1220312-stab.trf
+ VIDSTABTRANSFORMOPTS+=:crop=keep

....

The same in Linux bash:

...
+ declare -i VHEIGHT
+ ffprobe -v error -show_entries stream=width,height -of 
default=noprint_wrappers=1 P1220312.MP4
+ grep height
+ cut -f2 -d=
2160
++ ffprobe -v error -show_entries stream=width,height -of 
default=noprint_wrappers=1 P1220312.MP4
++ grep height
++ cut -f2 -d=
+ VHEIGHT=2160     # here is the desired value in the variable!!!
...

Any suggestions?


-
Köszönettel:
Vukovics Mihály


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