Cfrtjryk

How do I match file names abc_NNN.xyz? here is the directory content

[root@ tmp]# ls -ltr

total 0

-rw-r--r--. 1 root root 0 Jan  3 00:42 abc_123.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:42 abc_234.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:42 abc_345.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:43 abc_def_123.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:44 abc_def_234.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:44 abc_def_345.xyz

-rw-r--r--. 1 root root 0 Jan  3 01:57 abc_123_123.xyz

-rw-r--r--. 1 root root 0 Jan  3 01:57 abc_234_234.xyz

-rw-r--r--. 1 root root 0 Jan  3 01:57 abc_345_345.xyz

This one works for me

[root@ tmp]# ls -ltr abc_[0-9][0-9][0-9].xyz

-rw-r--r--. 1 root root 0 Jan  3 00:42 abc_123.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:42 abc_234.xyz

-rw-r--r--. 1 root root 0 Jan  3 00:42 abc_345.xyz

The problem is that in the real scenario I need to match abc_NNNNNNNNN.xyz so the expression is too large. I am looking for something similar to abc_[0-9]{3}.xyz, abc_[0-9]+3.xyz (obviously these doesn't work)

For the original simpler examples you listed, abc_[0-9]*.xyz will work. That obviously will match some things other than numbers, but will exclude the def files you've listed as the first character after the first underscore is not a digit in those cases.

For the more complicated examples, it's probably time to deploy find so we can actually use regular expressions:

$ ls

abc_123_123.xyz  abc_123.xyz  abc_234_234.xyz  abc_234.xyz  abc_345_345.xyz  abc_345.xyz  abc_def_123.xyz  abc_def_234.xyz  abc_def_345.xyz

$ find . -regex './abc_[0-9]+.xyz'

./abc_345.xyz

./abc_234.xyz

./abc_123.xyz

That's with GNU find, other variants may differ slightly.

If you're using bash, you could also make use of its extended globbing capabilites:

shopt -s extglob

ls abc_+([0-9]).xyz

Sample uutput:

abc_123456.xyz

abc_123.xyz

abc_1.xyz

abc_3456.xyz

abc_345.xyz

abc_56789.xyz

abc_567.xyz

The +([0-9]) expression matches one or more instances of any digit. This which will match the 'NNNN' pattern of any length.

As mentioned in POSIX glob — how to match one-or-more [:digit:] shell globing is not equal to regex. You are probably best of processing the ls output with grep in which case your originally mentioned abc_[0-9]{3}.xyz pattern would work.

You can combine the two as such:

[root@ tmp]# ls -ltr abc_[0-9]+.xyz | grep abc_[0-9]{3}.xyz