The awk command#

Awk is a general-purpose scripting language used for advanced text processing. It is mainly used as a reporting and analysis tool. Unlike most other procedural programming languages, Awk is data-driven, meaning that you need to define a set of operations to be performed on the input text and then it fetches the input data, processes it, and sends the results to standard output.

Syntax#

awk [ -F fs ] [ -v var=value ] [ 'prog' | -f progfile ] [ file ... ]

Parameters#

• -F fs: Set the input field separator to the regular expression fs.
• -v var=value: Assign the value to the variable var before executing the awk program.
• 'prog': The awk program.
• -f progfile: Specify the file progfile that contains the awk program to be executed.
• file ...: Files to be processed by the specified awk program.

Examples#

Suppose the example file example.txt contains the following data:

Print the third field of example.txt.

awk '{ print $3 }' example.txt
# 60
# 55
# 51
# 33
# 30

Match the groups that start with R using regular expressions.

awk '/^R/ { print $1,$2,$3,$4 }' example.txt
# Raptors Toronto 55 24

Use BEGIN and END to perform actions before and after processing records. The process is to output groups where the second field contains Tor.

awk 'BEGIN { print "Start Processing" }; $2 ~ /Tor/ {print $1,$2,$3,$4 }; END { print "End Processing" }' example.txt
# Start Processing
# Raptors Toronto 55 24
# End Processing

Daily Question#

References#