How to sort strings that contain a common prefix and suffix numerically from Bash?

Question

Here is a list of files:

some.string_100_with_numbers.in-it.txt
some.string_101_with_numbers.in-it.txt
some.string_102_with_numbers.in-it.txt
some.string_23_         


        

Answer 1

Try the following:

sort -t '_' -k 2n

• -t '_' (sets the delimiter to the underscore character)
• -k 2n (sorts by the second column using numeric ordering)

DEMO.

Answer 2

Use ls -lv

From the man page:

-v     natural sort of (version) numbers within text

Answer 3

In the general case, try the Schwartzian transform.

Briefly, break out the number into its own field, sort on that, and discard the added field.

# In many shells, use ctrl-v tab to insert a literal tab after the first \2
sed 's/^\([^0-9]*\)\([0-9][0-9]*\)/\2   \1\2/' file |
sort -n |
cut -f2-

This works nicely if the input doesn't have an obvious separator, like for the following input.

abc1
abc10
abc2

where you would like the sort to move the last line up right after the first.

Answer 4

If available, simply use sort -V. This is a sort for version numbers, but works well as a "natural sort" option.

$ ff=$( echo some.string_{100,101,102,23,24,25}_with_numbers.in-it.txt )

Without sort:

$ for f in $ff ; do echo $f ; done
some.string_100_with_numbers.in-it.txt
some.string_101_with_numbers.in-it.txt
some.string_102_with_numbers.in-it.txt
some.string_23_with_numbers.in-it.txt
some.string_24_with_numbers.in-it.txt
some.string_25_with_numbers.in-it.txt

With sort -V:

$ for f in $ff ; do echo $f ; done | sort -V
some.string_23_with_numbers.in-it.txt
some.string_24_with_numbers.in-it.txt
some.string_25_with_numbers.in-it.txt
some.string_100_with_numbers.in-it.txt
some.string_101_with_numbers.in-it.txt
some.string_102_with_numbers.in-it.txt