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    : Syntax for Regular Expression Data Patterns
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    7. Syntax for Regular Expression Data Patterns
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    PAN-OS Web Interface Help

    Syntax for Regular Expression Data Patterns

    Table of Contents

    Syntax for Regular Expression Data Patterns

    The general pattern requirements and syntax for creating data patterns depends on the pattern-matching engine that you enable: classic or enhanced (default).
    Pattern RequirementsClassicEnhanced
    Pattern length
    Requires 7 literal characters, which cannot include a period (.), an asterisk (*), a plus sign (+), or a range ([a-z]).
    Requires two literal characters.
    Case-insensitivity
    Requires you to define patterns for all possible strings to match all variations of a term.
    Example: To match any documents designated as confidential, you must create a pattern that includes “confidential,” “Confidential,” and “CONFIDENTIAL.”
    Allows you to use the i option on a sub-pattern.
    Example: ((?i)\bconfidential\b) matches ConfiDential
    The regular expression syntax in PAN-OS® is similar to traditional regular expression engines but every engine is unique. The Classic Syntax and Enhanced Syntax tables describe the syntax supported in the PAN-OS pattern-matching engines.
    Classic Syntax
    Pattern Syntax
    Description
    .
    Match any single character.
    ?
    Match the preceding character or expression 0 or one time. You must include the general expression inside parentheses.
    Example: (abc)?
    *
    Match the preceding character or expression 0 or more times. You must include the general expression inside parentheses.
    Example: (abc)*
    +
    Match the preceding character or regular expression one or more times. You must include the general expression inside parentheses.
    Example: (abc)+
    |
    Specify one “OR” another.
    You must include alternative substrings in parentheses.
    Example: ((bif)|(scr)|(exe)) matches bif, scr, or exe.
    -
    Specify a range.
    Example: [c-z] matches any character between c and z inclusive.
    [ ]
    Match any specified character.
    Example: [abz] matches any of the specified characters—a, b, or z.
    ^
    Match any character except those specified.
    Example: [^abz] matches any character except the specified characters—a, b, or z.
    { }
    Match a string that contains minimum and maximum.
    Example: {10-20} matches any string that is between 10 and 20 bytes inclusive. You must specify this directly in front of a fixed string and you can use only a hyphen (-).
    \
    Perform a literal match on any character. You must precede the specified character with a backslash (\).
    &amp
    The ampersand (& ) is a special character so, to look for & in a string, you must use &amp.
    Enhanced Syntax
    The enhanced pattern-matching engine supports all of the Classic Syntax as well as the following syntax:
    Pattern Syntax
    Description
    Shorthand character classes
    Symbols that stand for a character of a specific type, such as a digit or white space. You can negate any of these shorthand character classes by using uppercase characters.
    \s
    Match any whitespace character.
    Example: \s matches a space, tab, line break, or form feed.
    \d
    Match a character that is a digit [0-9].
    Example: \d matches 0.
    \w
    Matches an ASCII character [A-Za-z0-9_].
    Example: \w\w\w matches PAN.
    \v
    Match a vertical white space character, which includes all unicode line break characters.
    Example: \v matches a vertical white space character.
    \h
    Match horizontal white space, which includes the tab and all of the “space separator” unicode characters.
    Example: \h matches a horizontal white space character.
    Bounded repeat quantifiers
    Specify how many times to repeat the previous item.
    {n}
    Match exactly a number (n) of times.
    Example: a{2} matches aa.
    {n,m}
    {n,m} matches from n to m times.
    Example: a{2,4} matches aa, aaa, and aaaa
    {n, }
    {n,} matches at least n times.
    Example: a{2,} matches aaaaa in aaaaab.
    Anchor characters
    Specify where to match an expression.
    ^
    Match at the beginning of a string. Also matches after every line break when multi-line mode (m) is enabled.
    Example: Given the string abc, ^a matches a, but ^b doesn’t match anything because b doesn’t occur at the start of the string.
    $
    Match at the end of a string or before a newline character at the end of a string. Also matches before every line break when multi-line mode (m) is enabled.
    Example: Given the string abc, c$ matches c, but a$ doesn’t match anything because a doesn’t occur at the end of the string.
    \A
    Match at the beginning of a string. Doesn’t match after line breaks, even when multi-line mode (m) is enabled.
    \Z
    Match at the end of a string and before the final line break. Doesn’t match before other line breaks even when multi-line mode (m) is enabled.
    \z
    Match at the absolute end of a string. Doesn’t match before line breaks.
    Option modifiers
    Change the behavior of a sub-pattern. Enter (?<option>) to enable or (?-<option>) to disable.
    i
    Enable case-insensitivity.
    Example: ((?i)\bconfidential\b) matches ConfiDential.
    m
    Make ^ and $ match at the beginning and end of lines.
    s
    Make . match anything, including line break characters.
    x
    Ignore whitespace between regex tokens.

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