Question

I have a sample data in a log file

NODE-ID> command1

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam
nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat
volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation
ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

NODE-ID> command2

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam
nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat
volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation
ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

NODE-ID> command3

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam
nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat
volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation
ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

I have a file which is generated by sequential commands. I am not sure how can i extract data from the log file

suppose if I need to extract data from file

NODE-ID> command1

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam
nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat
volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation
ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

what is the best way to do so ? I have most my script written in shell script, I can use awk or sed. Please suggest

Answer 1

perl -ne 'sub BEGIN { $/="NODE-ID> "; } { if (/^command1/) { s:$/$::; print "$/$_"; }}'

Not sed/awk, but…it works.

This is awk:

awk 'BEGIN { RS="NODE-ID> "; } /^command1/ { print RS $0; }'

And inspired by CodeGnome, I add a sed option:

sed -n '/^NODE-ID> command1/,/^NODE-ID> / { /^NODE-ID> command1/ { p; d; }; /^NODE-ID> /q; p }'