Running ffmpeg in loop seems to change reading from file
Hi everyone,
I am fairly new to shell scripting. I want to read in numbers from a file (one number per line). This works perfectly fine
and yields the correct output:
If I however run a ffmpeg command in the loop
the output changes (I ommit the ffmpeg output and just give the echo command output):
If I add two spaces in the txt-file I read in, such as
the echo command returns the right numbers again - for some reason, the ffmpeg commands seems to result in the skipping of the first two characters in the new line.
If I put an additional for-loop around the while loop to loop over several files such as in
The first line of every file is read in correctly, but for all subsequent lines, the first two characters are skipped. Does anybody have any idea what is going on? I am very grateful for any hint.
My guess is that ffmpeg is reading two bytes from stdin. If you are using, or can use, kshell, then you can avoid that with code like this:
The while reads from the file descriptor opened by the exec statement and assigned to fd and thus isn't affected by what anything in the loop might read from stdin.
If you need to, or would rather use bash, then you'll have to specifically pick a file descriptor to use:
And, from my small bit of testing, you have to supply a hard number on the exec when using bash, this seems not to work: exec $fd<data-file
---------- Post updated at 13:04 ---------- Previous update was at 12:58 ----------
Kludgy, but this would work allowing the variable contents to be used when opening:
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333
222
111
file2.txt has
ccc
bbb
aaa
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data1
data2
data3
data4
$
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192.168.1.6
192.168.1.7
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Sorry if this is a repeated question ,
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