F    Regular Expressions

The event definition files use regular expression rules to determine whether there is a match between a given expression and the console output. Regular expressions are described in the grep(1) reference page. Regular expression symbols should not be confused with glob symbols * and ?.

The following special characters may be helpful when making changes to event definitions:

• ^ (circumflex)

  When used as the first character of an expression, it anchors an expression to the beginning of a line. For example, ^Unable to obtain requested swap space indicates that the expression must be at the beginning of a line.

• $ (dollar sign)

  At the end of a pattern, it causes that pattern to match only if the last matched character is the last character (not including the newline character) on a line. For example, Unable to obtain requested swap space$ indicates that the phrase must be at the end of a line.

• ^$ (circumflex and dollar sign)

  The construction ^pattern$ restricts the pattern to matching only an entire line. For example, the regular expression ^abcd$ matches lines containing the string abcd, where a is the first character on the line and d the last.

• . (period)

  When used outside a bracket expression, matches any single character.

• + (plus sign)

  Matches one or more occurrences of a character. For example, hel+o matches "hello" and "hellllo".

• .+ ( period and plus sign)

  Match any and all characters. It is similar to glob symbol *. For example, NFS3 server .+ not responding will produce a match with any characters substituted for .+ — provided that they are preceded by "NFS3 server" and succeeded by "not responding".