| Symbol | awk | csplit | egrep | emacs | expr | grep | perl | sed | vi | meaning |
|---|
| One-character matches |
| . | * | * | * | * | * | * | * | * | * | Match any 1 character |
| [set] | * | * | * | * | * | * | * | * | * | Match any character in set |
| [^set] | * | * | * | * | * | * | * | * | * | Match any character not in set |
| Quantifiers |
| R* | * | * | * | * | * | * | * | * | * | Match 0 or more of R |
| R+ | * | | * | * | | | * | | | Match 1 or more of R |
| R? | * | | * | * | | | * | | | Match 0 or 1 of R |
| R{n} | | | | | | | * | | | Match exactly n occurrences of R |
| R\{n\} | | | | | | * | | * | |
| R{n,m} | | | | | | | * | | | Match from n to m occurrences of R |
| R\{n,m\} | | | | | | * | | * | |
| Anchors |
| ^ | * | * | * | * | * | * | * | * | * | Match beginning of line |
| $ | * | * | * | * | * | * | * | * | * | Match end of line |
| \<text\> | | | | | | *1 | | | * | Match standalone word (text must be surrounded by non-word characters, beginning of line, or end of line) |
| \btext\b | | | | | | | * | | |
| Grouping |
| R1|R2 | * | | * | * | | | * | | | Match R1 or R2 |
| ( ) | * | | * | * | | | * | | | Group contents and remember what was matched |
| \( \) | | | | | * | | | * | * |
| Miscellaneous |
| \ | * | * | * | * | * | * | * | * | * | Turn off special meaning ("escape") |
| 1 This works with most versions of grep; if it does not, the -w option causes the entire pattern to be treated as a standalone word. |
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