Change the position of string in line

Question

I would like to move the first string between > and the first _ to the second position after the first _

This is to transform this:

>10E13JB10_Vacares_8__a1
blablabla
>10E13JB10_Vacares_8__a2
blablabla
>10E2JB10_Mulhacen_13__a1
blablabla

Into this:

>Vacares_10E13JB10_8__a1
blablabla
>Vacares_10E13JB10_8__a2
blablabla
>Mulhacen_10E2JB10_13__a1
blablabla

score 4 · Accepted Answer · edited Oct 11 '16 at 15:19

4

sed -e 's/^>\([^_]*\)_\([^_]*\)/>\2_\1/' -i file

Find the first two strings terminated by _, and reverse their order in the substitution. Since it only matches the first two strings, it does not modify or discard the rest of the line.

s/aaa/bbb/ - perform a substitution, replacing all occurrences of aaa with bbb
^ - begin of line
\(...\) - capture groups, which save the matched strings as \1 and \2
[^_]* - a character class matching all characters except _

edited Oct 11 '16 at 15:19

jpaugh

329

answered Oct 11 '16 at 14:11

Ipor Sircer

14,546
1
27
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1

You should explain what you're doing here at least a little bit. – Centimane Oct 11 '16 at 14:16
2

I agree with Centimane. Someone new to regexes will freak when they see this... I added a (prose) description, but it's under peer review. – jpaugh Oct 11 '16 at 14:48
Note that -i (for in place editing) is a GNU extension, not standard Sed. But this is still a good answer. Also see How to achieve portability with sed -i (in-place editing)? – Wildcard Nov 05 '16 at 02:44

Change the position of string in line

1 Answers1