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6.2. 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 bullet (Figure ) in Table 6.1. Items marked with a “P” are specified by POSIX; double-check your system's version. (On Solaris, the versions in /usr/xpg4/bin accept these items.) Full descriptions are provided after the table.

Table 6.1. Unix Metacharacters

Symboledexvisedawkgrep egrepAction
.Figure Figure Figure Figure Figure Figure Figure

Match any character.

*Figure Figure Figure Figure Figure Figure Figure

Match zero or more preceding.

^Figure Figure Figure Figure Figure Figure Figure

Match beginning of line/string.

$Figure Figure Figure Figure Figure Figure Figure

Match end of line/string.

\Figure Figure Figure Figure Figure Figure Figure

Escape following character.

[ ]Figure Figure Figure Figure Figure Figure Figure

Match one from a set.

\( \)Figure Figure Figure Figure  Figure  

Store pattern for later replay.[7]

\nFigure Figure Figure Figure  Figure  

Replay subpattern in match.

{ }    Figure P  Figure P

Match a range of instances.

\{ \}Figure   Figure  Figure  

Match a range of instances.

\< \>Figure Figure Figure      

Match word's beginning or end.

+    Figure   Figure

Match one or more preceding.

?    Figure   Figure

Match zero or one preceding.

|    Figure   Figure

Separate choices to match.

( )    Figure   Figure

Group expressions to match.

See Table 6-2.

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 6.1 are meaningful only in a search pattern.

In ed, ex, vi, and sed, the metacharacters in Table 6-2 are valid only in a replacement pattern.

Table 6.2. 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.

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6. Pattern MatchingBook Index6.3. Metacharacters
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