Rename Multiple files and add date before the files

Question

I have a folder contains one or more tar.gz files. I want to add current date before each files when the script run.

For example:

Two file name(those files will be created each day, but the name will remain the same):

file1.tar.gz 
file2.tar.gz

In first day(2011-10-07), those two files will be renamed to:

2011-10-07_file1.tar.gz
2011-10-07_file2.tar.gz

In next day(2011-10-08), they are changed to:

2011-10-08_file1.tar.gz
2011-10-08_file2.tar.gz

Finally, the folder contains the following files:

2011-10-07_file1.tar.gz
2011-10-07_file2.tar.gz
2011-10-08_file1.tar.gz
2011-10-08_file2.tar.gz

How to achieve this using one line? I tried to use "rename" command, but I can only add the date after the file, not before.

My code

cdate=`date +"%Y-%m-%d"`; rename .gz .gz.$cdate *.gz

Answer 1

Clearly, the key is to avoid renaming files that already have a date prefix.

cdate=$(date +"%Y-%m-%d")
shopt -s extglob
for file in !([0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]*.gz); do
  mv "$file" "${cdate}_$file"
done

Answer 2

Your example code might get you things like file1.2011-10-07.2011-10-08.tar.gz and I doubt that's what you want.

In addition, rename is not a standard command so it really depends on what yours does.

Since you say there are only ever a fixed number of files with fixed names, you could probably use a simple script like:

cdate=$(date +%Y-%m-%d)
for file in file1.tar.gz file2.tar.gz; do
    mv "$file" "$cdate"_"$file"
done

Answer 3

Assuming the files will never contain underscores in their names, a simple bash 4+ solution would be to use extglob:

shopt -s extglob
today=$(date +%F)
for f in ./!(*_*).tar.gz; do mv "$f" "$today"_"$f"; done

A more robust version:

shopt -s extglob
today=$(date +%F)
for f in ./!(????-??-??_*).tar.gz; do mv "$f" "$today"_"$f"; done

Answer 4

You can do it without resorting on bashisms (loops and/or extglob mode) and just use find, cut, grep and xargs.

find . -maxdepth 1 -type f | \
    cut -c3- | \
    grep -v '^\.' | \
    grep -v '^[0-9][0-9][0-9][0-9]\-[0-9][0-9]-[0-9][0-9]_' | \
    xargs -n 1 -I {} echo mv "{}" "`date +"%Y-%m-%d"`_{}"

Remove the echo to apply the changes instead of just printing the mv commands.