awk commands

The awk action is inside braces {}

ps | awk '{print $1}''

Default separator is spaces

Change it to , for csv

awk -F ","

Change to : for passwd file

awk -F ":"

awk -F ":" '{print $1}' /etc/passwd

Print out multiple columns

awk -F ":" '{print $1 $6 $7}' /etc/passwd

Add some tabs between outputs to make it more readable

awk -F ":" '{print $1"\t"$6"\t"$7}' /etc/passwd

Change the field separator

Work on data that has : as field separator

But output the data with - as the field separator 

awk 'BEGIN{FS=":" OFS="-"} {print $1,$6,$7}' /etc/password

Print the last column

awk -F "/" '/^\//' {print $NF} /etc/shells | uniq | sort

the /'s need to be escaped \/dev

df | awk '/\/dev\/loop/' {print $1"\t"$2}

Find all the /bin/fish running

ps -ef | awk '{if ($NF == "/bin/fish") print $0}'

For loop

awk 'BEGIN {for 1=1; i<=10; i++) print "The square root of", i, "is", i*i';}'

Matching a pattern

awk '$1 ~ /^[b,c]/ {print $0}' .bashrc

awk 'match ($0, /mystring/' {print $0}'' numbered.txt

Print a section (NR number of records, line numbers)

between lines 7 and 11

df | awk 'NR==7, NR==11 {print NR, $0}'

Getting a line count

awk 'END {print NR}' /etc/shells