How do I use BASH to change “A” Train.flac to 'A' Train in a filename?

Question

I've tried every combination of backslash and asterisk and curly brackets, nothing seems to work. I'm using the terminal in OS X and I would really appreciate it if someone could steer me straight.

Answer 1

You could use $() in order to task tr to do that conversion, then strip the file extension in a second step. It would look something similar to:

# Say FNAME is the variable that stores your original file name
# Convert the double quotes to single quotes:
SQFNAME=$(echo $FNAME|tr '""' "''")
# or, as an alternative in pure Bash (mind the shell character escaping):
SQFNAME=echo ${FNAME//\"/\'}
# then simply strip the extension
NEWFNAME=${SQFNAME%.flac}
# or, if you wanted to remove the extension delimited by the _last_ dot
NEWFNAME=${SQFNAME%.*}
# or, if you wanted to remove the extension delimited by the _first_ dot
NEWFNAME=${SQFNAME%%.*}

The "new" converted file name will be in the NEWFNAME variable now.

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Proof of concept:

#!/usr/bin/env bash
FNAME="\"A\" Train.flac"
echo "Unchanged name: $FNAME"
SQFNAME=${FNAME//\"/\'}
echo "Converted quotes: $SQFNAME"
NEWFNAME=${SQFNAME%.flac}
echo "New file name: $NEWFNAME"

Execution yields:

$ bash test.sh
Unchanged name: "A" Train.flac
Converted quotes: 'A' Train.flac
New file name: 'A' Train

Answer 2

I would use the prename Perl script that comes with most Perl installations (linked to rename in e.g. Debian based distributions, but on e.g. Fedora another rename is present, so research the case first if you are not sure, or just use prename as below):

prename 's/"/'\''/g' \"A\"\ Train.flac

The right tool for the right job.

To get a literal ', I first stop the current quoting environment, then escape a ', then start the quoting environment again.

---

I guess you don't really want to strip the file name extension and the question is just ambiguously worded, but if you do:

prename 's/"/'\''/g; s/\..*$//' \"A\"\ Train.flac

or

prename 's/"/'\''/g; s/\.flac$//' \"A\"\ Train.flac

Use the -n switch to just view the changes without applying them if you want to test the commands beforehand.