Bash: delete all but most recent n files with prefix x

Question

I have a directory of backups that looks like this:

-rw-r--r--   1 ftpuser ftponly   5610595 May 27 00:01 alpha-114.tar.asc   
-rw-r--r--   1 ftpuser ftponly  50559368 May 27 00:04 beta-211.tar.asc
-rw-r--r--   1 ftpuser ftponly  61320807 May 27 00:06 gamma-387.tar.asc
-rw-r--r--   1 ftpuser ftponly  43125044 May 27 00:07 epsilon-241.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107110560 Apr 26 04:33 zeta-7728.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107136555 Apr 27 00:29 zeta-7729.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107154163 Apr 28 00:29 zeta-7731.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107194763 May  1 00:33 zeta-7734.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107200582 May  2 00:33 zeta-7736.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107203436 May  4 00:32 zeta-7737.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107250397 May  7 00:33 zeta-7739.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107269251 May  8 00:26 zeta-7741.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107917088 May  9 00:32 zeta-7747.tar.asc
-rw-r--r--   1 ftpuser ftponly  1107914021 May 10 00:22 zeta-7748.tar.asc
-rw-r--r--   1 ftpuser ftponly  1113095971 May 11 00:32 zeta-7751.tar.asc
-rw-r--r--   1 ftpuser ftponly  1114420811 May 12 00:32 zeta-7756.tar.asc
-rw-r--r--   1 ftpuser ftponly  1114433146 May 13 00:31 zeta-7757.tar.asc
-rw-r--r--   1 ftpuser ftponly  1114437345 May 14 00:32 zeta-7758.tar.asc
-rw-r--r--   1 ftpuser ftponly  1114437862 May 16 00:29 zeta-7762.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115062371 May 17 00:29 zeta-7778.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115068367 May 18 00:30 zeta-7781.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115067272 May 19 00:24 zeta-7782.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115077719 May 20 00:26 zeta-7784.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115080120 May 22 00:25 zeta-7785.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115076554 May 23 00:33 zeta-7786.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115877146 May 24 00:26 zeta-7789.tar.asc
-rw-r--r--   1 ftpuser ftponly  1115967469 May 27 00:53 zeta-7795.tar.asc

I want to delete all but the most recent 3 of every file-prefix, so in this case all the zeta-****.tar.asc files except the last three. I have a kind of complicated perl script that accomplishes this, but I'd like do be able to do it with bash.

Slick snippets appreciated!

If it is complicated in Perl, it will be even more complicated in `bash`. — Sven, May 27 '11 at 10:24

user9517 · Answer 1 · 2011-05-30T11:50:40.533

2

You can use tail -n +3 to give you all bar the initial 3 lines of output from ls -1t e.g.

ls -1t zeta* | tail -n +3 | xargs rm

This lists all the files from newest to oldest in a single column which head then processes and outputs a list of files after the initial 3 (newest) files.

edited May 30 '11 at 11:50

answered May 27 '11 at 10:55

user9517

115,471
20
215
297

Yeah, but then I have to pass each prefix explicitly. – Frank Brenner May 30 '11 at 10:40

score 1 · Answer 2 · answered May 27 '11 at 10:37

1

ls -lt prefix*suffix | gawk ' { if ($NR > 3) print $NF } ' | xargs rm

Works for me. Isn't foolproof. No warranty. Your milleage may vary.

answered May 27 '11 at 10:37

Paweł Brodacki

6,511
20
23

...see my previous comment... – Frank Brenner May 30 '11 at 10:41

score 1 · Accepted Answer · answered May 27 '11 at 11:02

1

This should work for an arbitrary amount of prefixes, as long as they follow the prefix- name convention:

for i in `ls | sed 's/-.*//' | uniq`; do ls -t $i-* | awk '{if(NR>3) print}' | xargs rm -f; done

answered May 27 '11 at 11:02

opsguy

801
1
5
12

score 0 · Answer 4 · edited May 27 '11 at 19:30

0

This will delete all file older than 3 days. You can change it around. This basically looks for files whose modify time is less than now()-3days and deletes them.

find $PATH  -mtime -3 -type f -exec rm {}

You can optionally define a "-iname" flag to look for a specific pattern in the filenames

-iname suffix*prefix

For more options refer to the "find manpages"

edited May 27 '11 at 19:30

user9517

115,471
20
215
297

answered May 27 '11 at 12:40

Sameer

4,118
2
17
11

Thanks, but that will delete all files if they get old enough. – Frank Brenner May 30 '11 at 10:42

Bash: delete all but most recent n files with prefix x

4 Answers4