Name
awk
awk 'instructions'filesawk -fscript files
The awk script contained in instructions or script should be a series of /pattern/ {action} pairs. The action code is applied to each line matched by pattern. awk also supplies several functions for pattern matching.
Functions
match(text,pattern)If
patternmatches intext, return the position intextwhere the match starts. A failed match returns zero. A successful match also sets the variableRSTARTto the position where the match started, and the variableRLENGTHto the number of characters in the match.gsub(pattern,replacement,text)Substitute each match of
patternintextwithreplacement, and return the number of substitutions. Defaults to$0iftextis not supplied.sub(pattern,replacement,text)Substitute first match of
patternintextwithreplacement. A successful substitution returns 1, and an unsuccessful substitution returns 0. Defaults to$0iftextis not supplied.
Example
Create an awk file and then run it from the command line.
$cat sub.awk{ gsub(/https?:\/\/[a-z_.\\w\/\\#~:?+=&;%@!-]*/, "<a href=\"\&\">\&</a>"); print } $echo "Check the web site, http://www.oreilly.com/ catalog/repr" | awk -f sub.awk