Batch renaming files in command line and Xargs

Question

So, I have the following structure:

.
..
a.png
b.png 
c.png

I ran a command to resize them

ls | xargs -I xx convert xx -resize xx.jpg

Now my dir looks like this

.
..
a.png.jpg
a.png
b.png.jpg
b.png
c.png.jpg
c.png

The firs question is, how do i rename the file so that I can just have one extension. Not two. (basically, how do I clean up my original mistake)?

The second question is, in the future, using xargs, how do I change the extension of the file simular to second command?

Answer 1

My solution is similar to many of the xarg solutions, and particularly similar to Schleis'.

The difference here is a full regex manipulation with match references, and sed commands that properly ignore files that don't match so you don't need to prefilter your listing.

This is also safe for files with spaces and shell meta.

Change \2 in the replacement to any desired extension.

ls |
sed -nE 's/Rick\.and\.Morty\.(S03E[0-9]{2})\..*(\.[a-z0-9]{3})/"&" "Rick and Morty \1\2"/;T;p' |
xargs -n 2 mv

Explanation

The -n arg tell's sed not to print anything by default, the T command says skip to the end of the script if the previous s command didn't do a replacement, the p command prints the pattern space (only hit if the s command matches).

The & in the replacement is a reference to the contents of the original filename match.

If we replace mv in the command with bash -c 'echo "run($#) $@"' bash then we can see the number of times mv would be called, and with parameter count and value:

$ ls |
  sed -nE 's/Rick\.and\.Morty\.(S03E[0-9]{2})\..*(\.[a-z0-9]{3})/"&" "Rick and Morty \1\2"/;T;p' |
  xargs -n 2 bash -c 'echo "run($#) $@"' bash
run(2) Rick.and.Morty.S03E02.720p.HDTV.x264-BATV.mkv Rick and Morty S03E02.mkv
run(2) Rick.and.Morty.S03E03.720p.HDTV.x264-BATV.mkv Rick and Morty S03E03.mkv
run(2) Rick.and.Morty.S03E04.720p.HDTV.x264-BATV.mkv Rick and Morty S03E04.mkv
run(2) Rick.and.Morty.S03E05.HDTV.x264-BATV[ettv].mkv Rick and Morty S03E05.mkv
run(2) Rick.and.Morty.S03E06.720p.HDTV.x264-BATV.mkv Rick and Morty S03E06.mkv
run(2) Rick.and.Morty.S03E06.HDTV.x264-BATV.mkv Rick and Morty S03E06.mkv
run(2) Rick.and.Morty.S03E07.720p.HDTV.x264-BATV[ettv].mkv Rick and Morty S03E07.mkv
run(2) Rick.and.Morty.S03E08.720p.HDTV.x264-BATV.mkv Rick and Morty S03E08.mkv
run(2) Rick.and.Morty.S03E09.720p.HDTV.x264-BATV.mkv Rick and Morty S03E09.mkv
run(2) Rick.and.Morty.S03E10.720p.HDTV.x264-BATV.mkv Rick and Morty S03E10.mkv

Answer 2

Coming late to the party, but here's how you can rename files with xargs. Say you have a bunch of files named fileN.svg.png and you want to name them fileN.png where N could be a series of integers:

ls *.svg.png | xargs basename -s .svg.png | xargs -I {} mv {}.svg.png {}.png

The first xargs uses basename to strip off both .svg and .png to get a just filenameN. The second xargs receives that bare name and uses replacement to rename the file.