awk made easy – Andrea Zonca

awk ’/REGEX/ {print NR “ $9” $4”_“ $5 ;}' file.txt supports extended REGEX like perl ( e.g. [:blank:] Space or tab characters ) NR is line number NF Number of fields $ n is the column to be printed, $0 i s t h e w h o l e r o w i f i t o n l y n e c e s s a r y t o p r i n t c o l u m n s o f a f i l e i t i s e a s i e r t o u s e c u t : n a m e - a | c u t - d " " - f 1, 3, 11, 12 - d : o r - d " " i s t h e d e l i m i t e r - f 1, 3 a r e t h e f i e l d s t o b e d i s p l a y e d o t h e r o p t i o n s : - s d o e s n t s h o w l i n e s w i t h o u t d e l i m i t e r s, - - c o m p l e m e n t i s s e l f e s p l i c a t i v e c o n d i t i o n o n a s p e c i f i c f i e l d :$ <field> ~ /<string>/ Search for string in specified field.

you can use awk also in pipes:
ll | awk ‘NR!=1 {s+=$5} END {print “Average:” s/(NR-1)}’
END to process al file and then print results

tutorial on using awk from the command line:
http://www.vectorsite.net/tsawk_3.html#m1