How to select lines between two marker patterns which may occur multiple times with awk/sed

Question

Using awk or sed how can I select lines which are occurring between two different marker patterns? There may be multiple sections marked with these

Answer 1

This might work for you (GNU sed):

sed '/^abc$/,/^mno$/{//!b};d' file

Delete all lines except for those between lines starting abc and mno

Answer 2

Using sed:

sed -n -e '/^abc$/,/^mno$/{ /^abc$/d; /^mno$/d; p; }'

The -n option means do not print by default.

The pattern looks for lines containing just abc to just mno, and then executes the actions in the { ... }. The first action deletes the abc line; the second the mno line; and the p prints the remaining lines. You can relax the regexes as required. Any lines outside the range of abc..mno are simply not printed.

Answer 3

Don_crissti's answer from Show only text between 2 matching pattern?

firstmatch="abc"
secondmatch="cdf"
sed "/$firstmatch/,/$secondmatch/!d;//d" infile

which is much more efficient than AWK's application, see here.