Hi,
I am currently using grep -c to scan lines for certain data. I am just wondering if you can search a specific column of a file using grep -c.
Thanks (6 Replies)
I'm using grep in a shell and I was wondering:
Can I grep a file and then delete all files that contain what it returns?
So instead of grep 'blah' * and I have 50 files that have blah in it and I would have to delete all 50 manually, how would I just delete them all in one fell swoop? (3 Replies)
Hi,
I am executing the below command.
grep ".UPDATE" file1.txt | grep -v MQQUEUE > Myprog1
The expected output is all lines in file1.txt which have the string ".UPDATE" and dont contain the string MQQUEUE.
However, the output which I am getting is just searching for the string... (3 Replies)
My SQL is very rust and I'm having a problem with a query.
First, here are the tables involved.
Table `os`:
+--------------------------------+
| id | distro | version |
+--------------------------------+
| 1 | CentOS | 5.2 |
| 2 | RHEL | 5 |
| 3 ... (1 Reply)
Instead of using the following command
#dmesg | grep -v sendmail | grep -v xntpd
How can I use just one grep -v and give both arguments.
Please suggest
thanks (4 Replies)
Hello,
Is there a way in grep to remember patterns?
For eg: int a,b,c,d,a;
If a variable is declared twice, like in the previous example, I should be able to print only those lines.
Is there a way to print only the lines where the variable name occurs more than once, using grep... (1 Reply)
All,
I am wanting to find out if I can do this in one grep statement
grep -R failed * |grep -iEw 'Mar 1|Feb 2'
I want to search all files in a directory for the text "failed" AND a "date or date".
Currently, I am using the above running one grep and then piping it to another. It works,... (3 Replies)
is there anyway i can ask grep to only get the first line?
as in the top command line
line 1 <-- just grep this line
line 2
line 3
---------- Post updated at 04:24 PM ---------- Previous update was at 04:19 PM ----------
nvm.. found out that i can do it with
|head (12 Replies)
Discussion started by: Nick1097
12 Replies
LEARN ABOUT DEBIAN
tie::hash::regex
Tie::Hash::Regex(3pm) User Contributed Perl Documentation Tie::Hash::Regex(3pm)NAME
Tie::Hash::Regex - Match hash keys using Regular Expressions
SYNOPSIS
use Tie::Hash::Regex;
my %h;
tie %h, 'Tie::Hash::Regex';
$h{key} = 'value';
$h{key2} = 'another value';
$h{stuff} = 'something else';
print $h{key}; # prints 'value'
print $h{2}; # prints 'another value'
print $h{'^s'}; # prints 'something else'
print tied(%h)->FETCH(k); # prints 'value' and 'another value'
delete $h{k}; # deletes $h{key} and $h{key2};
or (new! improved!)
my $h : Regex;
DESCRIPTION
Someone asked on Perlmonks if a hash could do fuzzy matches on keys - this is the result.
If there's no exact match on the key that you pass to the hash, then the key is treated as a regex and the first matching key is returned.
You can force it to leap straight into the regex checking by passing a qr'ed regex into the hash like this:
my $val = $h{qr/key/};
"exists" and "delete" also do regex matching. In the case of "delete" all vlaues matching your regex key will be deleted from the hash.
One slightly strange thing. Obviously if you give a hash a regex key, then it's possible that more than one key will match (consider
c<$h{qw/./}>). It might be nice to be able to do stuff like:
my @vals = $h{$pat};
to get all matching values back. Unfortuately, Perl knows that a given hash key can only ever return one value and so forces scalar context
on the "FETCH" call when using the tied interface. You can get round this using the slightly less readable:
my @vals = tied(%h)->FETCH($pat);
ATTRIBUTE INTERFACE
From version 0.06, you can use attributes to define your hash as being tied to Tie::Hash::Regex. You'll need to install the module
Attribute::Handlers.
METHODS
FETCH
Get a value from the hash. If there isn't an exact match try a regex match.
EXISTS
See if a key exists in the hash. If there isn't an exact match try a regex match.
DELETE
Delete a key from the hash. If there isn't an exact match try a regex match.
AUTHOR
Dave Cross <dave@mag-sol.com>
Thanks to the Perlmonks <http://www.perlmonks.org> for the original idea and to Jeff "japhy" Pinyan for some useful code suggestions.
COPYRIGHT
Copyright (C) 2001-8, Magnum Solutions Ltd. All Rights Reserved.
LICENSE
This script is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO perl(1).
perltie(1).
Tie::RegexpHash(1)perl v5.10.0 2008-06-30 Tie::Hash::Regex(3pm)