问题
I want to look for the string "methodname(", but I am unable to escape the "(". How can I get
grep methodname( *
or
ack-grep methodname( *
to work?
回答1:
There's two things interpreting the (
: the shell, and ack-grep
.
You can use ''
, ""
, or \
to escape the (
from the shell, e.g.
grep 'methodname(' *
grep "methodname(" *
grep methodname\( *
grep
uses a basic regular expression language by default, so (
isn't special. (It would be if you used egrep
or grep -E
or grep -P
.)
On the other hand, ack-grep
takes Perl regular expressions as input, in which (
is also special, so you'll have to escape that too.
ack-grep 'methodname\(' *
ack-grep "methodname\\(" *
ack-grep methodname\\\( *
ack-grep 'methodname[(]' *
ack-grep "methodname[(]" *
ack-grep methodname\[\(\] *
回答2:
Try adding a \
before the (
.
Small demo:
$ cat file
bar
methodname(
foo
$ grep -n methodname\( file
2:methodname(
$
Enclosing the pattern in single or double quotes also works:
$ grep -n 'methodname(' file
2:methodname(
$ grep -n "methodname(" file
2:methodname(
$
来源:https://stackoverflow.com/questions/4761242/escaping-a-parenthesis-in-grep-ack