Linux shell script to add leading zeros to file names

Question

I have a folder with about 1,700 files. They are all named like 1.txt or 1497.txt, etc. I would like to rename all the files so that all the filena

Answer 1

There is a rename.ul command installed from util-linux package (at least in Ubuntu) by default installed.

It's use is (do a man rename.ul):

rename [options] expression replacement file...

The command will replace the first occurrence of expression with the given replacement for the provided files.

While forming the command you can use:

rename.ul -nv replace-me with-this in-all?-these-files*

for not doing any changes but reading what changes that command would make. When sure just reexecute the command without the -v (verbose) and -n (no-act) options

for your case the commands are:

rename.ul "" 000 ?.txt
rename.ul "" 00 ??.txt
rename.ul "" 0 ???.txt