Delete all files except the newest 3 in bash script

Question

Question: How do you delete all files in a directory except the newest 3?

Finding the newest 3 files is simple:

ls -t | head -3


        

Answer 1

As an extension to the answer by flohail. If you want to remove all folders except the newest three folders use the following:

find . -maxdepth 1 -mindepth 1 -type d -printf '%T@\t%p\n' |
 sort -t $'\t' -g | 
 head -n -3 | 
 cut -d $'\t' -f 2- |
 xargs rm -rf

The -mindepth 1 will ignore the parent folder and -maxdepth 1 subfolders.

Answer 2

Below worked for me: ( Cheers

Answer 3

The following looks a bit complicated, but is very cautious to be correct, even with unusual or intentionally malicious filenames. Unfortunately, it requires GNU tools:

count=0
while IFS= read -r -d ' ' && IFS= read -r -d '' filename; do
  (( ++count > 3 )) && printf '%s\0' "$filename"
done < <(find . -maxdepth 1 -type f -printf '%T@ %P\0' | sort -g -z) \
     | xargs -0 rm -f --

---

Explaining how this works:

• Find emits <mtime> <filename><NUL> for each file in the current directory.
• sort -g -z does a general (floating-point, as opposed to integer) numeric sort based on the first column (times) with the lines separated by NULs.
• The first read in the while loop strips off the mtime (no longer needed after sort is done).
• The second read in the while loop reads the filename (running until the NUL).
• The loop increments, and then checks, a counter; if the counter's state indicates that we're past the initial skipping, then we print the filename, delimited by a NUL.
• xargs -0 then appends that filename into the argv list it's collecting to invoke rm with.

Answer 4

ls -t | tail -n +4 | xargs -I {} rm {}

If you want a 1 liner

Answer 5

ls -t | tail -n +4 | xargs -I {} rm {}

Michael Ballent's answer works best as

ls -t | tail -n +4 | xargs rm --

throw me error if I have less than 3 file

Answer 6

Recursive script with arbitrary num of files to keep per-directory

Also handles files/dirs with spaces, newlines and other odd characters

#!/bin/bash
if (( $# != 2 )); then
  echo "Usage: $0 </path/to/top-level/dir> <num files to keep per dir>"
  exit
fi

while IFS= read -r -d $'\0' dir; do
  # Find the nth oldest file
  nthOldest=$(find "$dir" -maxdepth 1 -type f -printf '%T@\0%p\n' | sort -t '\0' -rg \
    | awk -F '\0' -v num="$2" 'NR==num+1{print $2}')

  if [[ -f "$nthOldest" ]]; then
    find "$dir" -maxdepth 1 -type f ! -newer "$nthOldest" -exec rm {} +
  fi
done < <(find "$1" -type d -print0)

Proof of concept

$ tree test/
test/
├── sub1
│   ├── sub1_0_days_old.txt
│   ├── sub1_1_days_old.txt
│   ├── sub1_2_days_old.txt
│   ├── sub1_3_days_old.txt
│   └── sub1\ 4\ days\ old\ with\ spaces.txt
├── sub2\ with\ spaces
│   ├── sub2_0_days_old.txt
│   ├── sub2_1_days_old.txt
│   ├── sub2_2_days_old.txt
│   └── sub2\ 3\ days\ old\ with\ spaces.txt
└── tld_0_days_old.txt

2 directories, 10 files
$ ./keepNewest.sh test/ 2
$ tree test/
test/
├── sub1
│   ├── sub1_0_days_old.txt
│   └── sub1_1_days_old.txt
├── sub2\ with\ spaces
│   ├── sub2_0_days_old.txt
│   └── sub2_1_days_old.txt
└── tld_0_days_old.txt

2 directories, 5 files