Code:

echo 'abc_lifecycle.log
  bcde_enjoy.log
  abc_twinkle.log' | awk -F [_.] '{ print $2 }'

basename abc_lifecycle.log .log|awk -F_ '{print $2}'
lifecycle

Quote:

Originally Posted by methyl See "man basename". Code: basename abc_lifecycle.log .log abc_lifecycle

Apart from the fact that that is not what the OP asked for, the basename command is entirely unnecessary in a POSIX shell (which is available on every system made in the last 10 to 15 years at least) and on any system before that which had ksh.

Code:

string=abc_lifecycle.log
temp=${string##*_}
printf "%s\n" "${temp%.*}"

echo abc_lifecycle.log | sed 's/\..*$//'

Quote:

Originally Posted by JeiPrakash But the problem is that i have just given only 3 log samples.In general i have 74 logs like this separated by such underscores.I need to get that 74 log names alone.

Where do you "have" them?

If they're in a file, use the awk script I posted with a filename instead of a pipe.