Tutorial by Examples

To assign variables from the command-line, -v can be used: $ awk -v myvar="hello" 'BEGIN {print myvar}' hello Note that there are no spaces around the equal sign. This allows to use shell variables: $ shell_var="hello" $ awk -v myvar="$shell_var" 'BEGIN {print m...

The option -v followed by an assignment of the form variable=value can be used to pass parameters to an awk program. This is illustrated by the punishment program below, whose job is to write count times the sentence “I shall not talk in class.” on standard output. The following example uses the v...

The awk language does not directly support variables local to functions. It is however easy emulate them by adding extra arguments to functions. It is traditional to prefix these variables by a _ to indicate that they are not actual parameters. We illustrate this technique with the definition of a...

Assignment arguments appear at the end of an awk invocation, in the same area as file variables, both -v assignments and argument assignments must match the following regular expression. (assuming a POSIX locale) ^[[:alpha:]_][[:alnum:]_]*= The following example assumes a file file containing th...