SSHREGEX(1) SSH2 SSHREGEX(1)
DESCRIPTION
This document describes the regular expressions (or glob-
bing patterns) used in filename globbing with scpg3 and
sftpg3 and in the sshd2_config and ssh-socks-proxy-con-
fig.xml configuration files.
Regex syntax used with scpg3 and sftpg3 is ZSH_FILEGLOB.
REGEX SYNTAX: EGREP
PATTERNS
The escape character is a backslash '\'. You can use it
to escape meta characters to use them in their plain char-
acter form.
In the following examples literal 'E' and 'F' denote any
expression, whether a pattern or a character.
( Start a capturing subexpression.
) End a capturing subexpression.
E|F Disjunction, match either E or F (inclusive). E is
preferred if both match.
E* Act as Kleene star, match E zero or more times.
E+ Closure, match E one or more times.
E? Option, match E optionally once.
. Match any character except for newline characters
(\n, \f, \r) and the NULL byte.
E{n} Match E exactly n times.
E{n,} or E{n,0}
Match E n or more times.
E{,n} or E{0,n}
Match E at most n times.
E{n,m} Match E no less than n times and no more than m
times.
[ Start a character set. See Section CHARACTER SETS
FOR EGREP AND ZSH_FILEGLOB.
$ Match the empty string at the end of the input or
at the end of a line.
^ Match the empty string at the start of the input or
at the beginning of a line.
ESCAPED TOKENS FOR REGEX SYNTAX EGREP
\0n..n The literal byte with octal value n..n.
\0 The NULL byte.
\[1-9]..x
The literal byte with decimal value [1-9]..x.
\xn..n or \0xn..n
The literal byte with hexadecimal value n..n.
\< Match the empty string at the beginning of a word.
\> Match the empty string at the end of a word.
\b Match the empty string at a word boundary.
\B Match the empty string provided it is not at a word
boundary.
\w Match a word-constituent character, equivalent to
[a:zA:Z0:9-].
\W Match a non-word-constituent character.
\a Literal alarm character.
\e Literal escape character.
\f Literal line feed.
\n Literal new line, equivalent to C's \n so it can be
more than one character long.
\r Literal carriage return.
\t Literal tab.
All other escaped characters denote the literal
character itself.
REGEX SYNTAX: ZSH_FILEGLOB (or TRADITIONAL)
PATTERNS
The escape character is a backslash '\'. With this you
can escape meta characters to use them in their plain
character form.
In the following examples literal 'E' and 'F' denote any
expression, whether a pattern or a character.
* Match any string consisting of zero or more charac-
ters. The characters can be any characters apart
from slashes (/). However, the asterisk does not
match a string if the string contains a dot (.) as
its first character, or if the string contains a
dot immediately after a slash. This means that the
asterisk cannot be used to match filenames that
have a dot as their first character.
If the previous character is a slash (/), or if an
asterisk (*) is used to denote a match at the
beginning of a string, it does match a dot (.).
That is, the asterisk (*) functions as normal in
Unix shell fileglobs.
? Match any single character except for a slash (/).
However, do not match a dot (.) if located at the
beginning of the string, or if the previous charac-
ter is a slash (/).
That is, the question mark (?) functions as normal
in Unix shell fileglobs (at least in ZSH, although
discarding the dot may not be a standard proce-
dure).
**/ Match any sequence of characters that is either
empty, or ends in a slash. However, the substring
'/.' is not allowed. This mimics the **/ construct
in ZSH. (Please note that '**' is equivalent to
'*'.)
E# Act as Kleene star, match E zero or more times.
E## Closure, match E one or more times.
( Start a capturing subexpression.
) End a capturing subexpression.
E|F Disjunction, match either E or F (inclusive). E is
preferred if both match.
[ Start a character set. (see below)
CHARACTER SETS FOR EGREP AND ZSH_FILEGLOB
A character set starts with '[' and ends at non-escaped
']' that is not part of a POSIX character set specifier
and that does not follow immediately after '['.
The following characters have a special meaning and need
to be escaped if meant literally:
- (minus sign)
A range operator, except immediately after '[',
where it loses its special meaning.
^ or ! (latter applies to ZSH_FILEGLOB)
If immediately after the starting '[', denotes a
complement: the whole character set will be comple-
mented. Otherwise literal. '^'.
[:alnum:]
Characters for which 'isalnum' returns true (see
ctype.h).
[:alpha:]
Characters for which 'isalpha' returns true (see
ctype.h).
[:cntrl:]
Characters for which 'iscntrl' returns true (see
ctype.h).
[:digit:]
Characters for which 'isdigit' returns true (see
ctype.h).
[:graph:]
Characters for which 'isgraph' returns true (see
ctype.h).
[:lower:]
Characters for which 'islower' returns true (see
ctype.h).
[:print:]
Characters for which 'isprint' returns true (see
ctype.h).
[:punct:]
Characters for which 'ispunct' returns true (see
ctype.h).
[:space:]
Characters for which 'isspace' returns true (see
ctype.h).
[:upper:]
Characters for which 'isupper' returns true (see
ctype.h).
[:xdigit:]
Characters for which 'isxdigit' returns true (see
ctype.h).
EXAMPLE
[[:xdigit:]XY] is typically equivalent to
[0123456789ABCDEFabcdefXY] .
It is also possible to include the predefined escaped
character sets into a newly defined one, so
[\d\s]
matches digits and whitespace characters.
REGEX SYNTAX: SSH
PATTERNS
The escape character is a tilde '~'. With this you can
escape meta characters to use them in their plain charac-
ter form.
NOTE: In configuration the backslash '\' is used to escape
the list separator (',').
In the following examples literal 'E' and 'F' denote any
expression, whether a pattern or a character.
( Start a capturing subexpression.
) End a capturing subexpression.
{ Start anonymous, non-capturing subexpression.
} End anonymous, non-capturing subexpression.
E|F Disjunction, match either E or F (inclusive). E is
preferred if both match.
E* Act as Kleene star, match E zero or more times.
E*? Act as Kleene star, but match non-greedily (lazy
match).
E+ Closure, match E one or more times.
E+? Closure, but match non-greedily (lazy match).
E? Option, match E optionally once.
E?? Option, but match non-greedily (lazy match).
. Match ANY character, including possibly the NULL
byte and the newline characters.
E/n/ Match E exactly n times.
E/n,/ or E/n,0/
Match E n or more times.
E/,n/ or E/0,n/
Match E at most n times.
E/n,m/ Match E no less than n times and no more than m
times.
E/n,/? , E/n,0/? , E/,n/? , E/0,n/? , E/n,m/?
The lazy versions of above.
[ Start a character set. See section CHARACTER SETS
FOR REGEX SYNTAX SSH.
>C One-character lookahead. 'C' must be either a lit-
eral character or parse as a character set. Match
the empty string anywhere provided that the next
character is 'C' or belongs to it.
<C One-character lookback. As above, but examine the
previous character instead of the next character.
$ Match the empty string at the end of the input.
^ Match the empty string at the start of the input.
ESCAPED TOKENS FOR REGEX SYNTAX SSH
~0n..n The literal byte with octal value n..n .
~0 The NULL byte.
~[1-9]..x
The literal byte with decimal value [1-9]..x .
~xn..n or ~0xn..n
The literal byte with hexadecimal value n..n .
~< Match the empty string at the beginning of a word.
~> Match the empty string at the end of a word.
~b Match the empty string at a word boundary.
~B Match the empty string provided it is not at a word
boundary.
~d Match any digit, equivalent to [0:9].
~D Match any character except a digit.
~s Match a whitespace character (matches space, new-
line, line feed, carriage return, tab and vertical
tab).
~S Match a non-whitespace character.
~w Match a word-constituent character, equivalent to
[a:zA:Z0:9-].
~W Match a non-word-constituent character.
~a Literal alarm character.
~e Literal escape character.
~f Literal line feed.
~n Literal new line, equivalent to C's \n so it can be
more than one character long.
~r Literal carriage return.
~t Literal tab.
All other escaped characters denote the literal character
itself.
CHARACTER SETS FOR REGEX SYNTAX SSH
A character set starts with '[' and ends at non-escaped
']' that is not part of a POSIX character set specifier
and that does not follow immediately after '['.
The following characters have a special meaning and need
to be escaped if meant literally:
: A range operator, except immediately after '[',
where it loses its special meaning.
- (minus sign)
Until next +, the characters, ranges, and sets will
be subtracted from the current set instead of
adding. If appears as the first character after
'[', start subtracting from a set containing all
characters instead of the empty set.
+ Until next -, the characters, ranges, and sets will
be added to the current set. This is the default.
[:alnum:]
Characters for which 'isalnum' returns true (see
ctype.h).
[:alpha:]
Characters for which 'isalpha' returns true (see
ctype.h).
[:cntrl:]
Characters for which 'iscntrl' returns true (see
ctype.h).
[:digit:]
Characters for which 'isdigit' returns true (see
ctype.h).
[:graph:]
Characters for which 'isgraph' returns true (see
ctype.h).
[:lower:]
Characters for which 'islower' returns true (see
ctype.h).
[:print:]
Characters for which 'isprint' returns true (see
ctype.h).
[:punct:]
Characters for which 'ispunct' returns true (see
ctype.h).
[:space:]
Characters for which 'isspace' returns true (see
ctype.h).
[:upper:]
Characters for which 'isupper' returns true (see
ctype.h).
[:xdigit:]
Characters for which 'isxdigit' returns true (see
ctype.h).
It is also possible to include the predefined escaped
character sets into a newly defined one, so
[~d~s]
matches digits and whitespace characters.
Also, escape sequences resulting in literals work inside
character sets.
EXAMPLE
[[:xdigit:]-a:e] is typically equivalent to
[0123456789ABCDEFf] .
AUTHORS
SSH Communications Security Corp.
For more information, see http://www.ssh.com.
SEE ALSO
sshd2_config(5), ssh-broker-config(5), scpg3(1), sftpg3(1)
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