Vrftsjtryk

How can I add numbers to the files in one directory?

In one directory I have files like below:

fileA

fileB

fileC

fileD

I want to prepend ascending numbers to them, like this:

1_fileA

2_fileB

3_fileC

4_fileD

Thank you in advance.

One of the solutions:

cd <your dir> then run in bash (copy and paste in command-line):

n=1; for f in *; do mv "$f" "$((n++))_$f"; done

Bash script case:

#!/bin/bash

n=1

for f in *

do

  if [ "$f" = "rename.sh" ]

  then

    continue

  fi

  mv "$f" "$((n++))_$f"

done

save it as rename.sh to dir with files to rename, chmod +x rename.sh then run it ./rename.sh

If there are more than 9 files, I would use printf to pad the number to get the expected sort order, like this

n=0

for f in *

    do printf -v new "%2d$((++n))_$f"

    echo mv -v -- "$f" "$new"

done

Remove echo when you see the correct result.

Explanation

In this line, do printf -v new "%2d$((++n))_$f" we create a format for the new filenames and put it into the variable new.

%2d is a 2 digit decimal number. Instead of 2d, you can use 3d etc to get another leading 0 (if you have more than 99 files).

((++n)) increments the variable n (which we set to 0 at the start of the script. Since it is iterated once each time the loop is run, files get incremented name prefixes.

-v makes mv print what will be changed.

-- in the mv statement is to prevent filenames that start with - being interpreted as options.

That’s a job for rename:

rename -n 'our $i; if (!$i) {$i++}; s/^/sprintf("%d_", $i++)/e' *

This defines a variable, increases it if it’s not set (else it would start with 0 instead of 1) and replaces the beginning of the filename with the number increasing it every time. You can change the format easily, e.g. to make it three-digit (001, 002, …) use "%03d_". Running it with -n only prints the changes, to actually perform the renaming remove this flag.

Example run

$ ls -1

fileA

fileB

fileC

fileD

$ rename -n 'our $i; if (!$i) {$i++}; s/^/sprintf("%d_", $i++)/e' *

rename(fileA, 1_fileA)

rename(fileB, 2_fileB)

rename(fileC, 3_fileC)

rename(fileD, 4_fileD)

$ rename 'our $i; if (!$i) {$i++}; s/^/sprintf("%d_", $i++)/e' *

$ ls -1

1_fileA

2_fileB

3_fileC

4_fileD