Rename files by incrementing a number within the filename

Question

I have a directory which contains numbered image files, something like this:

01.png
02.png
03.png
03.svg
04.png
05.png
06.jpg
07.png
08.png
09.png
09.svg
10.png

Sometimes there may be multiple versions of a file in different formats (eg. a png and svg version of the 03 and 09 files above) but the numbers are otherwise consecutive. Typically there are 40-80 such files in each directory. The numbers correspond to the order these images appear in a manuscript (a Word document, but that's not important). There is no other way to determine the order of the images.

If I add a new image to the manuscript I need to place a copy of the image in this directory with the correct numbering. So if the new image is the fifth in the manuscript I need to rename the files in the directory to this in order to make room for it:

01.png
02.png
03.png
03.svg
04.png
06.png
07.jpg
08.png
09.png
10.png
10.svg
11.png

What is the most straightforward way from the command line, or from a script or macro to renumber all the files starting at a certain number? I have a standard Fedora Linux install using bash.

Answer 1

I think that it should do the work:

#!/bin/bash

NEWFILE=$1

for file in `ls|sort -g -r`
do
    filename=$(basename "$file")
    extension=${filename##*.}
    filename=${filename%.*}

    if [ $filename -ge $NEWFILE ]
    then
        mv "$file" "$(($filename + 1))".$extension
    fi
done

Script takes one parameter - number of you new image.

PS. Put script in another directory than your images. In images directory there should be only images named in this way that you described.

Answer 2

This exact issue is covered in this article. Note that you would have to modify it to support the SVG and PNG formats, by adding a second MV step.

Answer 3

This would be easier in zsh, where you can use

• the On glob qualifier to sort matches in decreasing order (and n to use numerical order, in case the file names don't all have leading zeroes to the same width);
• the (l:WIDTH::FILLER:) parameter expansion flag to pad all numbers to the same width (the width of the larger number).

break=$1   # the position at which you want to insert a file
setopt extended_glob
width=
for x in [0-9]*(nOn); do
  n=${x%%[^0-9]*}
  if ((n < break)); then break; fi
  ((++n))
  [[ -n $width ]] || width=${#n}
  mv $x ${(l:$width::0:)n}${x##${x%%[^0-9]*}}
done

In bash, here's a script that assumes files are padded to a fixed width (otherwise, the script won't rename the right files) and pads to a fixed width (which must be specified).

break=$1      # the position at which you want to insert a file
width=9999    # the number of digits to pad numbers to
files=([0-9]*)
for ((i=#((${#files}-1)); i>=0; --i)); do
  n=${x%%[^0-9]*}
  x=${files[$i]}
  if ((n < break)); then continue; fi
  n=$((n + 1 + width + 1)); n=${n#1}
  mv -- "${files[$i]}" "$n${x##${x%%[^0-9]*}}"
done