{"id":111,"date":"2024-12-17T06:10:07","date_gmt":"2024-12-17T06:10:07","guid":{"rendered":"https:\/\/techkubo.com\/linux\/?p=111"},"modified":"2025-05-28T17:58:32","modified_gmt":"2025-05-28T17:58:32","slug":"linux-awk-command","status":"publish","type":"post","link":"https:\/\/techkubo.com\/linux\/linux-awk-command\/","title":{"rendered":"Linux – awk Command"},"content":{"rendered":"\n

The awk<\/code> command is a versatile and powerful text processing tool that allows you to search, extract, and manipulate data from text files or input streams. It uses pattern matching and can perform complex text transformations.<\/p>\n\n\n\n

Initial Example<\/h2>\n\n\n\n

Using awk<\/code> to print the first column of a file called data.txt<\/code>:<\/p>\n\n\n\n

<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\n
AWK Parameters<\/h2>\n\n\n\n
Parameter<\/th>Description<\/th><\/tr><\/thead>
-F sepstring<\/code><\/td>Set the input field separator to sepstring<\/code>. Equivalent to -v FS=sepstring<\/code>. If both -F<\/code> and -v<\/code> are used, the order of FS assignment is unspecified.<\/td><\/tr>
-f progfile<\/code><\/td>Use the file specified by progfile<\/code> as the source of the awk<\/code> program. A pathname of -<\/code> denotes standard input. Multiple -f<\/code> options concatenate the specified files as the program.<\/td><\/tr>
-v assignment<\/code><\/td>Pre-assign the variable assignment<\/code> before running the awk<\/code> program, including BEGIN<\/code> patterns. This can be used multiple times to set several variables.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Examples<\/h2>\n\n\n\n
1. Print Specific Columns<\/h4>\n\n\n\n
To print specific columns from a file:<\/p>\n\n\n\n
awk '{print $1, $3}' filename.txt<\/pre><\/div>\n\n\n\n
2. Filter and Print Lines Matching a Pattern<\/h4>\n\n\n\n
To print lines that match a specific pattern:<\/p>\n\n\n\n
awk '\/pattern\/ {print $0}' filename.txt<\/pre><\/div>\n\n\n\n
3. Perform Calculations on Columns<\/h4>\n\n\n\n
To perform calculations on columns and print the result:<\/p>\n\n\n\n
awk '{print $1, $2, $1 + $2}' filename.txt<\/pre><\/div>\n\n\n\n
4. Use Field Separators<\/h4>\n\n\n\n
To specify a custom field separator, use the -F<\/code> option. For example, if the file uses commas as separators:<\/p>\n\n\n\n
awk -F, '{print $1, $2}' filename.txt<\/pre><\/div>\n\n\n\n
5. Print Line Numbers<\/h4>\n\n\n\n
To print line numbers along with the content:<\/p>\n\n\n\n
awk '{print NR, $0}' filename.txt<\/pre><\/div>\n\n\n\n
6. Use Variables<\/h4>\n\n\n\n
To use variables in an awk<\/code> script:<\/p>\n\n\n\n
awk '{x = $1 + $2; print x}' filename.txt<\/pre><\/div>\n\n\n\n
7. Use Built-in Functions<\/h4>\n\n\n\n
To use built-in functions, such as length<\/code> to print the length of each line:<\/p>\n\n\n\n
awk '{print length($0)}' filename.txt<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\n
Linux Playground<\/h2>\n\n\n\n