| Wildcard | |
|---|---|
. |
Any |
\d |
Digit |
\D |
Negated of digit |
\w |
Word [0-9a-zA-Z_] |
\W |
Negated of word |
\s |
Whitespace |
\s |
Negated of whitespace |
[abc] |
Character class [a,b,c] |
^[abc] |
Negated of [a,b,c] |
(a|b)c |
Match ac, bc |
^ |
Begin of line |
$ |
End of line |
\ |
Escape next character |
| Quantity | |
|---|---|
* |
0-N |
? |
0-1 |
+ |
1-N |
a{2} |
aa |
a{2,4} |
aa - aaaa |
| Greedy | |
|---|---|
a*b |
Longest a*b |
a*?b |
Shortest a*b |
| Boundary | |
|---|---|
hello |
.*hello.* |
\bhello\b |
hello |
\Bhello\B |
\whello\w |
| Capturing Group | |
|---|---|
-ne 'print "$1\n" if /name=(\w+)/' |
Extract 1st match |
'print "$1 $2\n" if /name=(\w+) age=(\d+)/' |
Extract 1st, 2nd |
| Lookahead | |||
|---|---|---|---|
| Positive | car (?=run) |
Match car only if followed by run |
car run |
| Negative | car (?!run) |
Match car only if not followed by run |
car stop |
| Lookbehind | |||
|---|---|---|---|
| Positive | (?<=red) car |
Match car only if preceded by red |
red car |
| Negative | (?<!red) car |
Match cat only if not preceded by red |
blue car |
| Command line arguments | |
|---|---|
-e |
Execute command |
-E |
Execute with features |
-p |
Print all lines |
-n |
Not print automatically |
| Subtitude | |
|---|---|
-pe 's/foo/bar/' |
Replace first foo by bar |
-pe 's/foo/bar/g' |
Replace all foo by bar |
-pe 's/foo/bar/i' |
Ignore case insensitive |
-pe 's/(foo) (bar)/$2 $1/' |
Capure groups. Swap foo, bar |
| Split & Field | |
|---|---|
-F<regex> |
Split on regex |
-F: |
Split on : |
-F'[:,]' |
Split on : or , |
$F[0] $F[1] |
Fields 0, 1 |
@F |
All fields |
-F: -e 'print "$F[0] $F[1]\n"' |
Split on : and print fields 0, 1. |
-F: -e 'print "@F\n"' |
Split on : and print all fields. |