List files of particular extension

Question

Ok this is strange. I am using this code,

ls *.prj

To list all the files with the .prj extension in the dir but I am getting this error,

bash: /bin/ls: Argument list too long

I eventually wish to get the count of files and I was using,

ls *.prj | wc -l

But even this command is giving the same error. Any idea where I am going wrong?

devav2 · Answer 1 · 2012-11-15T20:36:32.460

11

Use find command instead

 find . -name "*.prj"

You can also combine the commands with find

find . -name "*.prj" -exec COMMAND {} \;

Hope this helps.

edited Nov 15 '12 at 20:36

answered Nov 15 '12 at 20:26

devav2

36,312

that would be correct if all the files in the directory were having only .prj extn, but I have files with same names but different extensions and your commands lists all of them – Sam007 Nov 15 '12 at 20:29
but by doing ls *.prj you are tyring to list the files with extn .prj right? – devav2 Nov 15 '12 at 20:37
the answer is above – Sam007 Nov 15 '12 at 20:44
can we do this for multiple extensions too? – Muhammad Omer Aslam Aug 07 '20 at 03:51

score 9 · Accepted Answer · answered Nov 15 '12 at 20:24

9

Nothing, there is a limit on the number of argument bash can deal with. Do

ls | grep '\.prj$' | wc -l

answered Nov 15 '12 at 20:24

January

35,952

Yup that works great, that is what I wanted. Let this 15 min rule pass and I will select this as the right answer – Sam007 Nov 15 '12 at 20:27

Gilles 'SO- stop being evil' · Answer 3 · 2020-03-16T13:13:53.400

3

Parsing the output of ls is unreliable. It will probably work in your case, but ls mangles unprintable characters. Here is a fully reliable way of counting the files matching a certain extension. This shell snippet creates an array containing the file names, then prints the number of elements in the array.

shopt -s nullglob
a=(*.prj)
echo ${#a[@]}

edited Mar 16 '20 at 13:13

answered Nov 15 '12 at 21:37

Gilles 'SO- stop being evil'

60,593

ok I tried this and echo is giving me value 17 but the actual value is 90419, which is correctly calculated by the other two commands above – Sam007 Nov 15 '12 at 21:46
2

@Sam007 Sorry, that was an error in my command, I used zsh syntax that gives a different result in bash. ${#a} in zsh calculates the length of the array, but in bash it gives the length of the first element, and you need ${#a[@]} to get the number of elements. – Gilles 'SO- stop being evil' Nov 15 '12 at 21:50
Yup that is working – Sam007 Nov 15 '12 at 22:00
Even if there is not a file with that extension, it outputs 1. And the list contains *prj – muyustan Mar 16 '20 at 05:45

List files of particular extension

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