how to rename files while copying?

Question

How would I copy (archive style where date isn't changed) all the files in a backup directory to the user's directory while renaming each file to remove the random string portion from the name (i.e., -2b0fd460_1426b77b1ee_-7b8e)?

cp from:

/backup/path/data/Erp.2014.02.16_16.57.03-2b0fd460_1426b77b1ee_-7b8e.etf

to:

/home/user/data/Erp.2014.02.16_16.57.03.etf

Each file will always start with "Erp." followed by the date-time stamp string followed by the random string and then the extension ".etf". I want to keep all name elements including the date-time stamp. I just want to remove the random string.

The random string allows multiple backups of the same file. However, in this case, I just ran fdupes and there are no duplicates. So I can simply restore all the files, removing the random string.

I'm looking for a one-line bash command to do it.

If that won't work, I could do it in two or more steps. I normally use KRename, but in this case I need to do it in bash. (I'm working remotely.)

Answer 1

You can use the cp command with the -a option

-a, --archive
       same as -dR --preserve=all

And then use a for loop to rename all files while copying them:

for file in Erp*etf; do
  cp -a $file destinationDirectory/${file%%-*}.etf
done

Ready. Start this command in the source directory.

Explanation: The %%-* will cut off all the characters after the first occurence of a hyphen/minus - and the .etf at the end again adds the file extension.

Well, and as a one liner, put it all in one line. :-) Like this

for file in Erp*etf; do cp -a $file destinationDirectory/${file%%-*}.etf; done

Answer 2

pax can do this all at once. You could do:

cd /backup/path/data && pax -wrs'/-.*$/.etf/' Erp*etf /home/user/data

pax preserves times by default, but can add -pe to preserve everything (best done as root) or -pp to preserve permissions , eg:

cd /backup/path/data && pax -wrs'/-.*$/.etf/' -pe Erp*etf /home/user/data

Otherwise (pax isn't usually available by default), surely it is better to do a copy then a rename:

cp -a /backup/path/data/Erp*.etf /home/user/data
rename 's/-.*$/.etf/' /home/user/data/Erp*.etf

This way there is not a different process started for each file.

Answer 3

In zsh, use zmv. Put this in your .zshrc:

autoload -U zmv
alias zcp='zmv -C'
alias zln='zmv -L'

Then use

zcp '/backup/path/data/(*)-[0-9A-Fa-f_]#.(*)' '/home/user/data/$1$2'

In bash:

zsh -c 'autoload zmv; zmv -C $0 $1' '/backup/path/data/(*)-[0-9A-Fa-f_]#.(*)' '/home/user/data/$1$2'

If you don't have zsh, a POSIX way uses pax (this copies directories recursively).

If you're on a restricted system with no zsh and no pax, you can use a loop:

for source in /backup/path/data/*-*.etf; do
  basename=${source##*/}
  cp "$source" "/home/user/data/${basename%-*}.${basename##*.}"
done

Answer 4

cp doesn't have that capability. I recall cpio being able to do that, but the current manpage says otherwise. However, (gnu) tar does have a --transform option:

 --transform, --xform EXPRESSION
       use sed replace EXPRESSION to transform file names

So you'd have a cmdline like:

(cd /backup/path/data; tar --create --transform 's/-.*-....//' .) | (cd /home/user/data; tar --extract)