Delete files with regular expression

Question

I Tried to delete files that starts with A and ends with 2 numbers but It doesn't do a thing.
What I tried:

rm ^A*[0..9]2$

Where am I wrong?

Dennis · Accepted Answer · 2012-02-22T18:41:01.267

104

You can use the following command to delete all files matching your criteria:

ls | grep -P "^A.*[0-9]{2}$" | xargs -d"\n" rm

How it works:

ls lists all files (one by line since the result is piped).
grep -P "^A.*[0-9]{2}$" filters the list of files and leaves only those that match the regular expression ^A.*[0-9]{2}$
- .* indicates any number of occurrences of ., where . is a wildcard matching any character.
- [0-9]{2} indicates exactly two occurrences of [0-9], that is, any digit.
xargs -d"\n" rm executes rm line once for every line that is piped to it.

Where am I wrong?

For starters, rm doesn't accept a regular expression as an argument. Besides the wildcard *, every other character is treated literally.

Also, your regular expression is slightly off. For example, * means any occurrences of ... in a regular expression, so A* matches A, AA, etc. and even an empty string.

For more information, visit Regular-Expressions.info.

edited Feb 22 '12 at 18:41

answered Feb 22 '12 at 18:19

Dennis

49,727

3

Beware of spaces in file names. – slhck Feb 22 '12 at 18:27
1

The -d"\n switch fixes the spaces problem. – Frg Feb 22 '12 at 19:14
3

Note - some distros (like Mac OS) don't have a grep -P (Perl regex). grep -E may work in this case. – bluescrubbie Oct 02 '13 at 20:59
1

I prefer using -I with xargs and always test with non-lethal commands first: xargs -d"\n" -I {} echo "{}" – jozxyqk Mar 24 '14 at 05:40
1

Parsing ls? See this question which points to this article. Because of the pitfalls you may rm what you don't want to. – Kamil Maciorowski Nov 15 '16 at 11:57
@Frg Beware of newlines in file names. Or other strange characters. – 8bittree Nov 16 '16 at 19:43
this won't work if ls or grep aliased with --color=always option and you will need to do \ls | \grep ... – αғsнιη Oct 12 '18 at 04:42
This is not the most robust solution (spaces in filenames), especially considering find does all this in one command. – qwr Feb 25 '20 at 21:58

score 81 · Answer 2 · answered Feb 22 '12 at 19:01

81

Or using find:

find your-directory/ -name 'A*[0-9][0-9]' -delete

This solution will deal with weird file names.

answered Feb 22 '12 at 19:01

cYrus

21,787

12

This is a great solution. I prefer it because it is simpler and you can omit the -delete flag at the end first to see if your regex is correct before mass deleting your files. – JAMESSTONEco Apr 14 '15 at 21:31
2

Furthermore you have more control on what you delete, for example adding -type f – Marco Sulla Jun 08 '16 at 08:12
Can this be used to delete files and folders? It does not work for non empty folders. – Alex Sep 09 '17 at 11:46
@Alex nope, the directory must be empty (it wasn't an OP requirement anyway), you can use the xargs approach with rm -f. – cYrus Sep 09 '17 at 13:54
also obligatory link to article about parsing ls – qwr Feb 25 '20 at 21:48
do we need specify mindepth? – jian Sep 14 '23 at 06:54

score 19 · Answer 3 · answered Feb 22 '12 at 19:46

19

See the filename expansion section of the bash man page:

rm A*[0-9][0-9]

answered Feb 22 '12 at 19:46

glenn jackman

26,306

worked nicely for me. – Nishanth Matha Mar 15 '17 at 06:09
This was the simplest, yet complete answer to the question. – Janac Meena Oct 17 '17 at 17:22
Will this work if the folder has a lot of files? – Itay Sep 03 '19 at 18:05

score 4 · Answer 4 · answered Nov 27 '19 at 08:40

4

find command works with regexes as well.

Check which files are gonna to be deleted

find . -regex '^A.*[0-9]{2}$'

Delete files

find . -regex '^A.*[0-9]{2}$' -delete

answered Nov 27 '19 at 08:40

Petr Javorik

236

This one doesn't work in it's current form. You need to define -regextype egrep to make {x,y} type quantifiers work. – Gergely Lukacsy Jul 10 '20 at 15:05

score 3 · Answer 5 · answered Jan 09 '19 at 13:35

3

This works on my mac:

rm $(ls | grep -e '^A*[0..9]2$')

answered Jan 09 '19 at 13:35

Ray

31
1

score 2 · Answer 6 · edited Nov 11 '16 at 00:14

2

The solution with regexp is 200 times better, even with that you can see which file will be deleted before using the command, cutting off the final pipe:

ls | grep -P "^A.*[0-9]{2}$"

Then if it's correct just use:

ls | grep -P "^A.*[0-9]{2}$" | xargs -d "\n" rm

This is 200 times better because if you work with Unix it's important to know how to use grep. It's very powerful if you know how to use it.

edited Nov 11 '16 at 00:14

Gareth

18,809

answered Nov 10 '16 at 19:25

Salvatore

29

1

This doesn't seem to add much beyond what Dennis's 4 year old answer already says. – 8bittree Nov 16 '16 at 19:48
1

"200 times" is a pretty specific. Lots of other commands are very powerful too, all you need to do is learn how to use them. – glenn jackman Mar 15 '17 at 11:22

Delete files with regular expression

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