Shell Programming and Scripting

Hi All
I'm trying to take a .flac file and use metaflac to write
the tag info into a file, Then read the title portion of the tag and rename the original .flac file with this info.

lets call this script renameflac

now on the command line if I type:

Code:

metaflac myfile.flac --export-tags-to=/tmp/tmp.txt

This puts a file called tmp.txt in the /tmp directory
and in this file it looks like this:
ALBUM=Self Esteem
ARTIST=The Offspring
COMPOSER=The Offspring
DESCRIPTION=
DISCID=0912a612
GENRE=Just Plain Wierd
MUSICBRAINZ_DISCID=o33.enTD6BY0zF2.Wn..dIpgsFI-
TITLE=Self Esteem
TRACKNUMBER=1
TRACKTOTAL=18

I figure I could grab the TITLE= info to rename the file but I get stuck here:

Code:

#!/bin/bash
for file in *.flac ; do
metaflac $file --export-tags-to=/tmp/tmp.txt
done

renameflac myfile.flac

This just hangs
Is this because the metaflac commands uses its flags after the file name?
And is this even possible with bash?
Thanks for your time.

I don't write bash-scripts, so i can't give you a complete solution, but a few suggestions:

1) If you use a wildcard expansion like "*.flac" and then rename the files matched by that wildcard the results may or may not get obfuscated. Rename the *.flac-files to something intermediate like "*.flac.processed" and in a last step (after the for .... *.flac... do.....done-loop has finished) rename them again.

2) Maybe this is not posing a problem here, but generally it is better not to use the "for file in * ; do ....done", but a pipeline instead:

Code:

find . -prune -name "*" -type f -print | while read file ; do
   ....
done

The reason is: wildcards are expanded by the shell. The shell tries to execute the line "for file in * ; do" and replaces the asterisk with a list of filenames matching it. Only then the command will be executed. If the wildcard now matches a very big list of files chances are you hit the limitation of the input line length (in POSIX 4k characters) and get an error. This will not be the case with the find command and the pipeline.

3) You write a file to /tmp without checking if this is possible. Usually it is, but it is a risk you are taking if you do not check that first. Two problems could arise: /tmp is full and you (your user account) is not allowed to write to there.

Either check first if you can indeed write or work in a pipeline instead of an intermediate file:

Code:

newname="$(metaflac myfile.flac --export-tags-to=- | sed -n 's/^TITLE=//p;q')"

Hope this helps.
bakunin

Thank you!
I belive I understand.
The problem using the find command is that the flac files are
named like this:
01_-_Track_1.flac
and the output file should be
Self_Esteem.flac

Actualy, The more I write and test this the less I understand

Thanks again for your time bakunin

while this works:

Code:

for file in *.flac ; do
          metaflac $file --export-tags-to=tmp/tmp.txt
           part1=$(awk '{FS="="} /ARTIST/{print $2}' tmp/tmp.txt |sed 's/ /_/g')
           part2=$(awk '{FS="="} /TITLE/{print $2}' tmp/tmp.txt |sed 's/ /_/g')
           mv $file ${part1}_$part2.flac
 mv tmp/tmp.txt tmp/${part1}_$part2.txt
done

This doesn't:

Code:

find . -prune -name "*" -type f -print | while read file ; do
          metaflac $file --export-tags-to=tmp/tmp.txt
           part1=$(awk '{FS="="} /ARTIST/{print $2}' tmp/tmp.txt |sed 's/ /_/g')
           part2=$(awk '{FS="="} /TITLE/{print $2}' tmp/tmp.txt |sed 's/ /_/g')
           mv $file ${part1}_$part2.flac
 mv tmp/tmp.txt tmp/${part1}_$part2.txt
done

Any Idea?
Thanks again

You're pruning everything. You need to let find at least not prune the current directory. Try this one:

find . ! -name . -prune -name \*.flac -type f -print


and by the way, make sure you have read this alert.

Yep, I figured that out earlier, Its amazing what a -v after bash will do . Thanks!!!
Also Thank you for the alert link Pererabo.

Perderabo has always told you how to solve the find problem - sorry for my sloppiness. Still, the above lines give me headaches: why use two different tools for a purpose where one would suffice?

Code:

part1="$(sed -n '/ARTIST/ {;s/^.*=//;s/ /_/g;p;}' tmp/tmp.txt)"
part2="$(sed -n '/TITLE/ {;s/^.*=//;s/ /_/g;p;}' tmp/tmp.txt)"

does the same.

bakunin