Cut the first and the last part of a string in bash

Question

I have a string having this formats:

aa_bb_cc_dd
aa_bb_cc_dd_ee_ff

I want to obtain:

bb_cc
bb_cc_dd_ee

I've tried 'cut', but I didn't manage to obtain what I wanted.

Answer 1

when using bash you can use built-ins for this task:

strip_headtail() {
 local s=$1
 ## strip the head
 s=${s#*_}
 ## strip the tail
 s=${s%_*}

 echo ${s}
}

strip_headtail aa_bb_cc_dd
strip_headtail aa_bb_cc_dd_ee_ff

you might want to check the bash-manual (man bash) for more information on this. search for Remove matching prefix pattern resp. Remove matching suffix pattern.