Zmv command to rename file after matching pattern

You can use the prename command to rename files based on a transformation written in Perl.

Let's start simple. To rename all the .jpg files in a directory, changing all - to _, we can just use the s operator (we could also use tr). The Perl code is executed to transform each file name.

prename 's!-!_!g' *.jpg

To change the number sequence(s) at the end to a simple counter, we introduce a counter variable. I use the global variable $a as a counter (introducing extra variables is more complicated). The regular expression (\.[^/.]*)$ matches the file extension, and $1 in the replacement text stands for what the parenthesized group matched.

prename 's!-!_!g; ++$a; s!_[0-9_]+(\.[^/.]*)$!_$a$1!' *.jpg

Note that the files are renamed in the order given by the file name arguments, i.e. the order of expansion of *.jpg determines the numbering of the files.

Alternatively, we can initialize the counter explicitly with a BEGIN block.

prename 'BEGIN {$a = 1;} s!-!_!g; s!_[0-9_]+(\.[^/.]*)$!_$a$1!; ++$a;' *.jpg

To perform this in every subdirectory of the current directory, call find.

find -type d -exec sh -c 'cd "$1" && prename "$0" *.jpg' 's!-!_!g; ++$a; s!_[0-9_]+(\.[^/.]*)$!_$a$1!' {} \;

zmv does not read from standard input.

I would probably use find with mv here, or zmv with a zsh filename glob, but not both, and without involving grep at all. Using grep should be done on text that is divided into lines, not filenames (which could potentially include embedded newlines).

With filename globs (will only act on the current directory, and only on non-hidden files):

zmv '^TFLM *' 'TFLM $f'

Recursively, not renaming directories, including hidden files and files in hidden directories like find would:

zmv '(**/)(^TFLM *)(#qD^/)' '${1}TFLM $2'

With find (but without the conflict handling of zmv, so adding a -i option for safety):

find . ! -type d ! -name 'TFLM *' -exec sh -c '
    for pathname do
       mv -i "$pathname" "${pathname%/*}/TFLM ${pathname##*/}"
    done' sh {} +

In bash (for the current directory only, excluding hidden files):

shopt -s extglob
for name in !(TFLM *); do
    mv -i -- "$name" "TFLM $name"
done

Or, in bash with the Perl rename utility:

shopt -s extglob
rename 's|/|/TFLM |' ./!(TFLM *)

(without the ./, some variants would fail if there were file names starting with -. Not all variants support -- to mark the end of options).