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Using awk for Text Processing ​

The awk command mainly used for manipulate, extract data and generating reports

Printing all line ​

To display all lines in a file, use awk with the print $0 action, where $0 represents the entire line:

bash
awk '{print $0}' employee.txt

output:

Name Postition Department
Anto manager accounting
Budi manager finance
Cecil manager HR
Dinda assistant marketing
Eko supervisor IT
Farah hr_officer HR
Gita senior_analyst finance

Printing specific columns ​

Extract specific columns (fields) using $1, $2, etc., where numbers correspond to field positions. Use \t for tab-separated output:

bash
awk '{print $1 "\t" $3}' employee.txt

output:

Name    Department
Anto    accounting
Budi    finance
Cecil   HR
Dinda   marketing
Eko     IT
Farah   HR
Gita    finance

Printing all lines that match specific pattern ​

Filter lines that contain a specific pattern using a regular expression:

bash
awk '/finance/ {print $0}' employee.txt

output:

Budi manager finance
Gita senior_analyst finance

Count and print matched pattern ​

Count the number of lines matching a pattern and display the total:

bash
awk '/m/{++total} END {print "Total matched = ", total}' employee.txt

output:

Total matched =  5

before count ( for clarity )

bash
$ awk '/m/ {print $0}' employee.txt
Name Postition Department
Anto manager accounting
Budi manager finance
Cecil manager HR
Dinda assistant marketing

Saving output from AWK to different file ​

Redirect output to a new file using the > operator. For example, filter lines containing the letter "o":

bash
awk '/o/ {print $0}' employee.txt > output.txt

output:

bash
$ cat output.txt
Name Postition Department
Anto manager accounting
Eko supervisor IT
Farah hr_officer HR
Gita senior_analyst finance

Useful flags ​

  • -F: Specifies a custom field separator (e.g., -F"," for CSV files).

    Example: awk -F"," '{print $1}' data.csv

  • -f: Reads an awk program from a file instead of the command line.

    Example: awk -F"," '{print $1}' data.csv

  • {}: Encloses actions to perform when a pattern matches.

Additional notes ​

  • NR: Built-in variable for the current line number.
  • NF: Built-in variable for the number of fields in the current line.
  • Example: awk '{print NR ": " $0}' employee.txt prefixes each line with its line number.