awk command examples

Question 1

Fields in awk

Answer 1

Question 2

Inserting a couple of tabs and a string

Answer 2

kelly@octarine ~/test> ls -ldh * | grep -v total | \ awk ‘{ print “Size is “ $5 “ bytes for “ $9 }’

Size is 160 bytes for orig Size is 121 bytes for script.sed

Size is 120 bytes for temp_file

Size is 126 bytes for test

Size is 120 bytes for twolines

Size is 441 bytes for txt2html.sh

Question 3

take out any number of columns and even reverse the order

Answer 3

kelly@octarine ~> df -h | sort -rnk 5 | head -3 | \ awk ‘{ print “Partition “ $6 “\t: “ $5 “ full!” }’

Partition /var : 86% full!

Partition /usr : 85% full!

Partition /home : 70% full!

Question 4

displays only local disk device information, networked file systems are not shown

Answer 4

kelly is in ~> df -h | awk ‘/dev\/hd/ { print $6 “\t: “ $5 }’

/ : 46%

/boot : 10%

/opt : 84%

/usr : 97%

/var : 73%

/.vol1 : 8%

Question 5

search the /etc directory for files ending in “.conf” and starting with either “a” or “x”, using extended regular expressions

Answer 5

Question 6

In order to precede output with comments, use the BEGIN statement

Answer 6

Question 7

The END statement can be added for inserting text after the entire input is processed

Answer 7

Question 8

awk script contains awk statements defining patterns and actions

Answer 8

Question 9

input field separator

Answer 9

kelly is in ~> awk ‘BEGIN { FS=”:” } { print $1 “\t” $5 }’ /etc/passwd

–output omitted–

kelly Kelly Smith

franky Franky B.

eddy Eddy White

willy William Black

cathy Catherine the Great

sandy Sandy Li Wong

Question 10

input field separator in awk script

Answer 10

kelly is in ~> cat printnames.awk

BEGIN { FS=”:” } { print $1 “\t” $5 }

kelly is in ~> awk -f printnames.awk /etc/passwd –output omitted–

Question 11

The output field separator

Answer 11

kelly@octarine ~/test> cat test

record1 data1

record2 data2

kelly@octarine ~/test> awk ‘{ print $1 $2}’ test record1data1

record2data2

kelly@octarine ~/test> awk ‘{ print $1, $2}’ test

record1 data1

record2 data2

Question 12

output record separator

Answer 12

kelly@octarine ~/test> awk ‘BEGIN { OFS=”;” ; ORS=”\n–>\n” } \ { print $1,$2}’ test

record1;data1

–>

record2;data2

–>

Question 13

count the total number of records

Answer 13

kelly@octarine ~/test> cat processed.awk

BEGIN { OFS=”-“ ; ORS=”\n–> done\n” } { print “Record number “ NR “:\t” $1,$2 } END { print “Number of records processed: “ NR }

kelly@octarine ~/test> awk -f processed.awk test Record number 1: record1-data1

–> done

Record number 2: record2-data2

–> done

Number of records processed: 2

–> done