awk

• File manipulation

• Reads from std in and writes to std out

• Basically does the operation between {...} on every line

Identity Op

cat README.md | awk '{print $0}'
OR
awk '{print $0}' README.md

Variables

$0 - WHOLE LINE

$1, $2, $3 - index for line split by whitespace

$NF - last field

$(NF-2)

NR is row number

Change Field Seperator

Splits on colon for $1, $2, $3

awk '{print $2}' logs.txt | awk 'BEGIN{FS=":"}{print $1}' | sed 's/\[//'

Get Text between two text

awk -v FS="(<a>|</a>)" '{print $2}'

If

awk '{if ($(NF-2) == "200") {print $0}}' logs.txt

Culumulative

awk '{a+=$(NF-2); print "Total so far:", a}' logs.txt

#only care about final state
awk '{a+=$(NF-2)}END{print "Total:", a}' logs.txt

Other Examples

awk '{print NR ") " $1 " -> " $(NF-2)}' logs.txt