Renaming Files By Adding Numbers Prefixes In File Names

Question

I have a list of files which have number prefixes e.g 1-filename.txt 2-filename.txt ..so on . I found that I skipped a file name as 45-filename.txt . I have files from 1-filename.txt to 100-filename.txt in that directories . Now I want to rearrange all the files with number prefixes without losing their actual name(e.g filename.txt) by creating a bash script but failed to do that. The script I have created as below.

#!/bin/bash

n=1
for i in *.txt;
do
        file=$(ls -v "$i"  | awk -F- ' { print $NF }')
        mv  $i "$n-${file}"
        let n=n+1
done

But I am not getting required output.

note files have spaces in its name e.g : 1-my first file.txt 2-my second file.txt ....so on.

`ls -v "$i"` ? just `echo "$i"`. `note files have spaces in its name` Then __quote__ it. `mv "$i"` — KamilCuk, Dec 24 '20 at 11:51
It's not clear what you are trying to achieve. By the look of your code, you are overwriting a file every time with the mv command as n never changes? — Raman Sailopal, Dec 24 '20 at 11:51
@RamanSailopal I am trying to re-write their file names by removing previous number prefixes and adding same prefixes again because one number is skipped by mistaken. — ITGUYAKAY, Dec 24 '20 at 12:05

glenn jackman · Answer 1 · 2020-12-24T15:43:58.080

I would use an array to store the current filename "tail", indexed by the filename prefix number:

files=()
for file in *-*.txt; do
    n=${file%%-*}    # everthing before the first "-"
    name=${file#*-}  # everthing after the first "-"
    files[n]=$name
done

Iterating over the array indices occurs in numerical order:

c=0
for n in "${!files[@]}"; do
    if (( n != ++c )); then
        echo mv "${n}-${files[n]}" "${c}-${files[n]}"
    fi
done

A demo:

$ touch 1-abc.txt 2-def.txt 3-ghi.txt 8-foo.txt 12-bar.txt 100-baz.txt

$ for file in *-*.txt; do
>     n=${file%%-*}    # everthing before the first "-"
>     name=${file#*-}  # everthing after the first "-"
>     files[n]=$name
> done

$ declare -p files
declare -a files=([1]="abc.txt" [2]="def.txt" [3]="ghi.txt" [8]="foo.txt" [12]="bar.txt" [100]="baz.txt")

$ c=0

$ for n in "${!files[@]}"; do
>     if (( n != ++c )); then
>         echo mv "${n}-${files[n]}" "${c}-${files[n]}"
>     fi
> done
mv 8-foo.txt 4-foo.txt
mv 12-bar.txt 5-bar.txt
mv 100-baz.txt 6-baz.txt

Remove the echo if it looks good for you.

This does not handle 2 files having the same numerical prefix: only the last one (alphabetically speaking) is stored in the array. — glenn jackman, Dec 24 '20 at 15:46

Renaming Files By Adding Numbers Prefixes In File Names

1 Answers1