Ytdyklly

I am trying to batch-rename a bunch of files in my shell, and even though there is plenty of material about it on the internet, I cannot seem to find a solution for my specific case.

I have a bunch of files that have (what appears to be) a "timestamp-id":

abc_128390.png

abc_138493.png

abc_159084.png

...

that I'd like to exchange for a counter:

abc_001.png

abc_002.png

abc_003.png

...

My (plenty) naïve approach would be something like:

mv abc_*.png abc_{001..123}.png

Also, I could not figure out a way to make it work with a for-loop.

FWIW, unfortunately rename is not available on this particular system.

Any advice would be greatly appreciated!

I can't think of a solution that handles incrementing the counter in a more clever way, but this should work:

i=0

for fi in abc_??????.png; do

    mv "$fi" abc_$i.png

    i=$((i+1))

done

It should be safe to use abc_*.png because it is expanded before the first mv is ever executed, but it can be useful to be very specific in that you only want files with a six-character timestamp at the end.

With zsh:

typeset -A count

incr='++count[$1/$2]'

(zmv -n '([^0-9]##)<->(*)(#qn)' '$1${(l:3::0:)$((incr))}$2')

Remove the -n when happy.

Example:

$ ls

a1b.png  abc_128390.png  abc_159084.png  x12y.png

a2b.png  abc_138493.png  a.png           x2y.png

$ typeset -A count

$ incr='++count[$1/$2]'

$ (zmv -n '([^0-9]##)<->(*)(#qn)' '$1${(l:3::0:)$((incr))}$2')

mv -- a1b.png a001b.png

mv -- a2b.png a002b.png

mv -- abc_128390.png abc_001.png

mv -- abc_138493.png abc_002.png

mv -- abc_159084.png abc_003.png

mv -- x2y.png x001y.png

mv -- x12y.png x002y.png

With rename utility as part of Perl packages, you would do:

rename -n 'our $i; s/_.*/sprintf("_%03d.png", $i++)/e' *.png

Note: -n is for dry run, remove it to rename apply on files.

Avoid overwriting existing files:

i=1

for fi in abc_??????.png; do

    a="abc_$(printf '%04d' "$i").png"

    if [[ -e $a ]]; then

        echo "file $a exist, not moving $fi"

    else

        mv "$fi" "$a"

    fi

    i=$((i+1))

done

you can use cut to cut out parts of the filename, for example, if you want to rename files like

"1 first.jpg"

"2 second.jpg"

...

to

"10 first.jpg"

"20 second.jpg"

...

you can use

for i in *jpg; do

  mv -iv "$i" "$(echo "$i"|cut -d  -f1)0 $(echo "$i"|cut -d  -f2-99)";

done