Enumerate substitutions with sed or awk

Question

Given the plain text file with lines

bli foo bla
 abc
 dfg
bli foo bla
 hik
 lmn

what sed or awk magic transforms it to

bli foo_01 bla
 abc
 dfg
bli foo_02 bla
 hik
 lmn

so that every occurence of 'foo' is replaced by 'foo_[occurence number]'.

Answer 1

This probably isn't what you require, but it might give some ideas in the right direction.

Administrator@snadbox3 ~
$ cd c:/tmp

Administrator@snadbox3 /cygdrive/c/tmp
$ cat <<-eof >foo.txt
> foo
>  abc
>  dfg
> foo
>  hik
>  lmn
> eof

Administrator@snadbox3 /cygdrive/c/tmp
$ awk '/^foo$/{++fooCount; print($0 "_" fooCount);} /^ /{print}' foo.txt
foo_1
 abc
 dfg
foo_2
 hik
 lmn

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EDIT:

I'm a day late and a penny short, again ;-(

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EDIT2:

Character encodings is another thing to lookout for... Java source code isn't necessarily in the systems default encoding... it's quit UTF-8 encoded, to allow for any embedded "higher order entities" ;-) Many *nix utilities still aren't charset-aware.

Answer 2

awk '!/foo/||sub(/foo/,"&_"++_)' infile

Use gawk, nawk or /usr/xpg4/bin/awk on Solaris.

Answer 3

This is another way to express radoulov's answer

awk '/foo/ {sub(/foo/, "&_" sprintf("%02d",++c))} 1' infile

You should take care that you don't match "foobar" while looking for "foo":

gawk '/\<foo\>/ {sub(/\<foo\>/, "&_" sprintf("%02d",++c))} 1'