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Metacharacters, Listed by Unix Program

Some metacharacters are valid for one program but not for another. Those that are available to a Unix program are marked by a checkmark (✓) in Table 20-1. Items marked with a P are specified by POSIX; double-check your system’s version. Full descriptions are provided after the table.

Table 20-1. 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.[a]
\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.
[a] Stored subpatterns can be replayed during matching. See Table 20-2.

Note that in ed , ex , vi , and sed , you specify both a search pattern (on the left) and a replacement pattern (on the ...