Replace patterns that are inside delimiters using a regular expression call

Question

I need to clip out all the occurances of the pattern \'--\' that are inside single quotes in long string (leaving intact the ones that are outside single quotes). <

Answer 1

You can use the following sed script, I believe:

:again
s/'\(.*\)--\(.*\)'/'\1\2'/g
t again

Store that in a file (rmdashdash.sed) and do whatever exec magic in your scripting language allows you to do the following shell equivalent:

sed -f rmdotdot.sed < file containing your input data

What the script does is:

:again <-- just a label

s/'\(.*\)--\(.*\)'/'\1\2'/g

substitute, for the pattern ' followed by anything followed by -- followed by anything followed by ', just the two anythings within quotes.

t again <-- feed the resulting string back into sed again.

Note that this script will convert '----' into '', since it is a sequence of two --'s within quotes. However, '---' will be converted into '-'.

Ain't no school like old school.