Remove comments from file but preserve strings

Remove comments from file but preserve strings containing the comment symbol

sed '/#/!b;s/^/\n/;ta;:a;s/\n$//;t;s/\n\(\("[^"]*"\)\|\('\''[^'\'']*'\''\)\)/\1\n/;ta;s/\n\([^#]\)/\1\n/;ta;s/\n.*//' file

Explanation

/#/!b if the line does not contain a # bail out
s/^/\n/ insert a unique marker (\n)
ta;:a jump to a loop label (resets the substitute true/false flag)
s/\n$//;t if marker at the end of the line, remove and bail out
s/\n\(\(“[^”]*”\)\|\(‘\”[^’\”]*’\”\)\)/\1\n/;ta if the string following the marker is a quoted one, bump the marker forward of it and loop.
s/\n\([^#]\)/\1\n/;ta if the character following the marker is not a #, bump the marker forward of it and loop.

References

  1. Shamelessly plagiarized from http://stackoverflow.com/a/13551154/3569534

Comment whole section from ini file

Instead of using the ansible ini_file state=absent section=”Zabbix”, you can use this instead, to comment out the section. I realize you can just do a backup=yes option, but for the quick cases where you don’t want to fire up ansible:

tmpfile1=$( mktemp ); sed -r -e '/^\[/i#ENGLISH877' ~/foo | sed -r -e '/^\[Zabbix\]/,/ENGLISH877/s/^/#/;' | sed -r -e '/#ENGLISH877/d' > ${tmpfile1}; cat ${tmpfile1} > ~/foo

Explanation

The first sed statement inserts a new line with content “#ENGLISH877” (random string that will be unlikely to cause collisions) right before the start of each new section.
The second sed statement then modifies the section specified (“Zabbix”) and inserts comments at the beginning.
The last sed removes all instances of the random string we inserted.