Replace dots with underscores in right part of the line

Question

Say I have this piece of text:

some.blah.key={{blah.woot.wiz}}
some.another.foo.key={{foo.bar.qix.name}}
+ many other lines with a variable number of words separated by dots within {{ and }}

I'd like the following outcome after replacing dots with underscores in the right part (between the {{ and }} delimiters):

some.blah.key={{blah_woot_wiz}}
some.another.foo.key={{foo_bar_qix_name}}
...

I'm looking for the appropriate regex to perform the replacement in a one-liner sedcommand`.

I'm on a lead with this one: https://regex101.com/r/8wsLHo/1 but it capture all dots, including those on the left part, which I don't want. I tried this variation to exclude those on the left part but then it doesn't capture anything anymore: https://regex101.com/r/d7WAmX/1

Your delimiters are `{{` and `}}` so I assume you can have individual `{` or `}` chars within your text, e.g. `some.blah.key={{abc { def } ghi}}`, right? You should include that in your sample input/output or you'll get solutions that fail when that occurs. — Ed Morton, Nov 23 '16 at 02:34

score 4 · Accepted Answer · answered Nov 22 '16 at 21:22

4

You can use a loop:

sed ':a;s/\({{[^}]*\)\./\1_/;ta' file

:a defines a label "a"
ta jumps to "a" when something is replaced.

answered Nov 22 '16 at 21:22

Casimir et Hippolyte

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A very clever solution. – Cyrus Nov 22 '16 at 21:28
@Cyrus: Thanks <°))))))))> – Casimir et Hippolyte Nov 22 '16 at 21:36
I played with it and stripped it down a bit. To replace (with GNU sed) to the right of `=`: `sed -r ':a;s/(=.*)\./\1_/;ta' file` and left of `=`: `sed -r ':a;s/\.(.*=)/_\1/;ta' file` – Cyrus Nov 22 '16 at 22:41
Thank you, it did the job well. I'm curious if it's possible to do this with a single regex in say, Java, without resorting to sed additional semantic (loop here) ? – Gilles Philippart Nov 23 '16 at 21:41
@GillesPhilippart: yes you can do it using the `\G` anchor. pcre: https://regex101.com/r/X7UIrS/1 or java: https://regex101.com/r/X7UIrS/2 – Casimir et Hippolyte Nov 23 '16 at 23:23

score 2 · Answer 2 · edited Apr 13 '17 at 12:38

I came up with this quite complex one-liner:

sed "h;s/=.*/=/;x;s/.*=//;s/\./_/g;H;x;s/\n//"

explanations:

h: put line in hold buffer
s/=.*/=/: clobber right part after =
x: swap to put line in main buffer again, first part in hold buffer
s/.*=//: clobber left part before =
s/\./_/g: perform replacement of dots now that there's only right part in main buffer
H: append main buffer to hold buffer
x: swap buffers again
s/\n//: remove linefeed or both parts appear on separate lines

that was quite fun, but maybe sed is not the best tool to perform that operation, this rather belongs to code golf

Replace dots with underscores in right part of the line

2 Answers2