Script to rename multiple files

[wakatana]

Hello

input files:

01 - album - track001.mp3
09 - album - track009.mp3

desired output files:

track01.mp3
track09.mp3

works perfect:

ls *.mp3 | sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp'

also works perfect

#!/bin/bash
FS=$'\n'	# Delimiter set to newline (do not include another whitespaces)
for x  in *.mp3
do
 echo $x
done
unset IFS

But when i want to "compose" both commands it gives me no output

#!/bin/bash
FS=$'\n'
for x  in *.mp3
do
 echo "`sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x"`"
done
unset IFS

also my goal using mv in for loop is worthless if this simple echo did not work. What I am doing wrong ? I am Bash newbie trying to learn scripting, so if someone could do that in bash it would be nice. Many Thanks

[Cabhan]

I am going to guess that the problem here has to do with quoting (dealing with multiple levels of quotes in Bash can be a pain). Fortunately, you can simplify your script. Simply change it to this:

#!/bin/bash
FS=$'\n'
for x  in *.mp3
do
 sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x"
done
unset IFS

There is no need to echo "`command`". A line that is unquoted is simply executed (for instance, in your original script, the "echo" is executed: this is unnecessary.

Having said that, I don't understand why you are using this final script in any case. The first solution that you posted (piping the output of ls into sed) is the more efficient way to do this, and is certainly the easiest. If it's just a learning experience, then all is good, but if you're looking for a final solution, go with the first one .

Hope this helps.

[wakatana]

Hello I use echo for "debugging purposes". If i omit echo i definetly lost output of script (Or am i wrong ?).

I treid also followings for viewing output (but no result):

sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x" | echo
sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x" >> output

Simply when i run the script i get jus blank output consist of (number of *.mp3) newlines.

what i am trying to do is simple copy files: from "01 - album - track001.mp3" format to "track01.mp3" format

#!/bin/bash
FS=$'\n'
for x  in *.mp3
do
  cp "$x" "`sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x"`"
done
unset IFS

gives following output:

mv: cannot move `01 - album - track001.mp3' to `': No such file or directory
mv: cannot move `02 - album - track002.mp3' to `': No such file or directory
mv: cannot move `03 - album - track003.mp3' to `': No such file or directory
mv: cannot move `04 - album - track004.mp3' to `': No such file or directory
mv: cannot move `05 - album - track005.mp3' to `': No such file or directory
mv: cannot move `06 - album - track006.mp3' to `': No such file or directory
mv: cannot move `07 - album - track007.mp3' to `': No such file or directory
mv: cannot move `08 - album - track008.mp3' to `': No such file or directory
mv: cannot move `09 - album - track009.mp3' to `': No such file or directory

I think this task can't be done just using simple piping, if i am wrong correct me.
Thank you

[aram535]

I think you're better off doing the rename, and the 00 -> 0 replacement in two steps, it's just making it harder for no extra gain.

echo $foo | awk '{print $5}' should split on space and give you the .mp3 filename.

After you do the rename, you can go back and find and replace 00 with 0, with sed 's/00/0/'.

[wakatana]

OK I made it!

#!/bin/bash
FS=$'\n'
for x  in *.mp3
do
 var="`echo -ne $x | sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' `"
 cp "$x" "$var"
done
unset IFS

but is stil strange of me why

var="`echo -ne $x | sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' 
is not the same thing like i did before
var="`sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x"`"

[wakatana]

OK I made it!

but is stil strange of me why

var="`echo -ne $x | sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' 
is not the same thing like i did before
var="`sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' "$x"`"

now i know this bot arent the same....
first one print the string with echo, then does sed on this string and finaly stores it to variable.
the second do the sed on the contents of the file and stores it to variable... and this is mistake