file name change under linux bash

[whynot]

Hi everyone
I need a command line script that can change all (there are 8 folders perhaps i could apply each of them)folder contents files such as 10001.DAT 10002.DAT 10003.DAT 10004.DAT to 10001.mp3 10002.mp3 10003.mp3

Thanks.

[alf55]

within each directory do:

for fn in *.DAT; do mv ${fn} ${fn%DAT}mp3; done

[Rubberman]

within each directory do:

for fn in *.DAT; do mv ${fn} ${fn%DAT}mp3; done

You might also want to check out the rename command, and use that with find.

[drl]

Hi.

You might be able to avoid find by making use of the shell filename expansion facility. The perl substitution-expressions are not trivial, but for this case are fairly straight-forward. Here are before-and-after situations for several files in 2 directories:

#!/usr/bin/env bash

# @(#) s1	Demonstrate renaming files with perl-expressions, rename.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C tree rename

# Create and list directories.
./create

pl " Directories and files:"
tree

pl " Results, renaming, expecting message:"
rename 's/\.DAT$/.mp3/' d1/* d2/*.DAT
tree

exit 0

prodcuing:

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
GNU bash 3.2.39
tree v1.5.2 (c) 1996 - 2008 by Steve Baker, Thomas Moore, Francesc Rocher, Kyosuke Tokoro 
rename - ( /usr/bin/rename, 2009-05-27 )

-----
 Directories and files:
.
|-- create
|-- d1
|   |-- 10001.DAT
|   |-- 10002.DAT
|   |-- 10003.DAT
|   |-- 99.DATA
|   `-- xxDAT
|-- d2
|   |-- 10001.DAT
|   |-- 10002.DAT
|   |-- 10009.DAT
|   `-- 10009.mp3
|-- readme.txt
`-- s1

2 directories, 12 files

-----
 Results, renaming, expecting message:
d2/10009.DAT not renamed: d2/10009.mp3 already exists
.
|-- create
|-- d1
|   |-- 10001.mp3
|   |-- 10002.mp3
|   |-- 10003.mp3
|   |-- 99.DATA
|   `-- xxDAT
|-- d2
|   |-- 10001.mp3
|   |-- 10002.mp3
|   |-- 10009.DAT
|   `-- 10009.mp3
|-- readme.txt
`-- s1

2 directories, 12 files

The two filename expressions on the rename command show that one can simply ask for all filenames to be looked at, or one can be more specific.

There is a limitation on the length of commands, and so the rename command might become too long, in which case, separate invocations of rename could be used, or find may need to be used as noted by Rubberman. A find-xarg combination is often used to balance large numbers of files with efficiency, but one can begin simply and move on to more complex solutions as circumstances demand.

See man rename for details, especially option "--no-act" to allow you to see what would be done. Backups are always useful when experimenting with new commands ... cheers, drl

[whynot]

Thanks all of u.

One more question
Is it possible to add this directory names to this new mp3 files?

- New Files
--10002.DAT
--10003.DAT
--10004.DAT

New_Files_10001.mp3
New_Files_10002.mp3
New_Files_10003.mp3

Old Files
Old_Files_10001.mp3
Old_Files_10002.mp3

like that ?

[atreyu]

Try this script out. It will look for all files ending in ".DAT" (case-insensitive) in the current working dir and will recurse into subdirectories, too.

It will first print what it is going to do (move file.dat file.mp3) but i've commented out the actual command that does the move. run it as is, to see if it works right (does it determine the mp3 filename correctly, etc.). If it does look okay, then uncomment the line with the mv command (should be line 20 or so).

you'll notice that all the magic that changes the name from "New File/10001.DAT" to "New_File_10001.mp3" is in the sed command around line 16. See if you can figure out what it is doing (hint: there are 4 separate sed commands in there, semicolon-delimited).

#!/bin/bash

# modify the Input Field Separator (to handle file/dir names with spaces)
OIFS=$IFS
IFS='
'

# run a recursive find to look for DAT files in the current working dir
dats=($(find . -type f -iname '*.dat' 2>/dev/null))
echo "Found [${#dats[*]}] DAT files"

# loop thru all DAT files found
for dat in ${dats[*]}; do

  # get mp3 file name
  mp3=$(echo "$dat"|sed -e 's|^\./||;s|/|_|g;s| |_|g;s|\.dat$|.mp3|gi')

  # move the DAT file to the new mp3 filename
  printf "Moving $dat to $mp3 ... "
#  out=$(mv -v $dat $mp3 2>&1)
  if [ $? -eq 0 ]; then
    echo OK
  else
    echo FAILED
    printf "$out\n"
    exit 1
  fi

done
IFS=$OIFS