Question

I want to transform a line that looks like this:

any text #any text# ===#text#text#text#===#

into:

any text #any text# ===#texttexttext===#

As you can see above I want to remove the # between ===# and ===#
The number of # that are supposed to be removed can be any number.

Can I do this with sed?

Answer 1

Give this a try:

sed 'h;s/[^=]*=*=#\(.*\)/\1/;s/\([^=]\)#/\1/g;x;s/\([^=]*=\+#\).*/\1/;G;s/\n//g' inputfile

It splits the line in two at the first “=#”, then deletes all “#” that aren’t preceded by an “=”, then recombines the lines.

Let me know if there are specific cases where it fails.

Edit:

This version, which is increasingly fragile, works for your new example as well as the original:

sed 'h;s/[^=]*=[^=]*=*=#\(.*\)$/\1/;s/\([^=]\)#/\1/g;x;s/\([^=]*=[^=]*=\+#\).*/\1/;G;s/\n//g' inputfile