7.3. Metacharacters, Listed by Unix Program

Some metacharacters are valid for one program but not for another. Those that are available are marked by a bullet (·) in Table 7-1. (This table is correct for most commercial Unix systems, including Solaris.) Items marked with a "P" are specified by POSIX; double-check your system's version. (On Solaris, the versions in /usr/xpg4/bin and /usr/xpg6/bin accept these items.) Full descriptions were provided in the previous section.

Table 7-1. Unix metacharacters

Symbol	ed	ex	vi	sed	awk	grep	egrep	Action
.	·	·	·	·	·	·	·	Match any character.
*	·	·	·	·	·	·	·	Match zero or more preceding.
^	·	·	·	·	·	·	·	Match beginning of line/string.
$	·	·	·	·	·	·	·	Match end of line/string.
\	·	·	·	·	·	·	·	Escape following character.
[ ]	·	·	·	·	·	·	·	Match one from a set.
\( \)	·	·	·	·		·		Store pattern for later replay.*
\n	·	·	·	·		·		Replay subpattern in match.
{ }					· P		· P	Match a range of instances.
\{ \}	·			·		·		Match a range of instances.
\< \>	·	·	·					Match word's beginning or end.
+					·		·	Match one or more preceding.
?					·		·	Match zero or one preceding.
|					·		·	Separate choices to match.
( )					·		·	Group expressions to match.
Stored subpatterns can be "replayed" during matching. See Table 7-2.

Note that in ed, ex, vi, and sed, you specify both a search pattern (on the left) and a replacement pattern (on the right). The metacharacters in Table 7-1 are meaningful only in a search pattern.

In ed, ex, vi , and sed, the metacharacters in Table 7-2 are valid only in a replacement pattern.

Table 7-2. Metacharacters in replacement patterns

Symbol	ex	vi	sed	ed	Action
\	·	·	·	·	Escape following character.
\n	·	·	·	·	Text matching pattern stored in \( \).
&	·	·	·	·	Text matching search pattern.
~	·	·			Reuse previous replacement pattern.
%				·	Reuse previous replacement pattern.
\u \U	·	·			Change character(s) to uppercase.
\l \L	·	·			Change character(s) to lowercase.
\e	·	·			Turn off previous \u or \l.
\E	·	·			Turn off previous \U or \L.