07-24-2008
\1 is a backreference to what is matched in the parenthesis in the regexp. So /(.)\1/ finds a double occurance of whatever (.) matched. It is similar to $1 but is used inside the regexp. It is discussed in some detail here:
perlretut - perldoc.perl.org
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1. Shell Programming and Scripting
Hi,
Can anyone help me to find regular expression for the following in Perl?
"The string can only contain lower case letters (a-z) and no more than one of any letter."
For example: "table" is accepted, whether "dude" is not.
I have coded like this:
$str = "table";
if ($str =~ m/\b()\b/) {... (4 Replies)
Discussion started by: evilfreakz
4 Replies
2. Shell Programming and Scripting
I have got numbers like
l255677
l376039
l188144
l340482
l440700
l254113
to match the numbers starting with '13' what would be the regex
=~/13(.*)/ =======>This is not working ....
But for user123,user657
regex =~/user(.*)/ ========>works
Thanks for help..!! (7 Replies)
Discussion started by: trina_1
7 Replies
3. Shell Programming and Scripting
I am having trouble parsing rpm filenames in a shell script.. I found a snippet of perl code that will perform the task but I really don't have time to rewrite the entire script in perl. I cannot for the life of me convert this code into something sed-friendly:
if ($rpm =~ /(*)-(*)-(*)\.(.*)/)... (1 Reply)
Discussion started by: suntzu
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4. UNIX for Dummies Questions & Answers
Hi,
I get the following when I cat a file *.log
xxxxx
=====
dasdas gwdgsg fdsagfsag agsdfag
=====
random data
=====
My output should look like :
If the random data after the 2nd ==== is null then OK should be printed else
the random data should be printed.
How do I go about this... (5 Replies)
Discussion started by: manutd
5 Replies
5. Programming
HI,
I'm new to perl and need simple regex for reading a file using my perl script.
The text file reads as -
filename=/pot/uio/current/myremificates.txt
certificates=/pot/uio/current/userdir/conf/user/gamma/settings/security/... (3 Replies)
Discussion started by: jhamaks
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6. Programming
Hi Guys
I have the following regex
$OSRELEASE = $1 if ($output =~ /(Mac OS X (Server )?10.\d)/);
output is currently
Mac OS X 10.7.5
when the introduction of Mac 10.8 output changes to
OS X 10.8.2
they have dropped the Mac bit so i changed the regex to be (2 Replies)
Discussion started by: ab52
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7. Programming
Hello,
I'm trying to get a quick help on regex since i'm not a regular programmer.
Below is the line i'm trying to apply my regex to..i want to use the regex in a for loop and this line will keep on changing.
subject=... (4 Replies)
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8. Shell Programming and Scripting
Could anyone please make me understand how the ?= works below ..
After executing this I am getting the same output.
$string="I love chocolate.";
$string =~ s/chocolate(?= ice)/vanilla/;
print "$string\n"; (2 Replies)
Discussion started by: scriptscript
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9. Shell Programming and Scripting
I am not a big expert in regex and have just little understanding of that language.
Could you help me to understand the regular Perl expression:
^(?!if\b|else\b|while\b|)(?:+?\s+){1,6}(+\s*)\(*\) *?(?:^*;?+){0,10}\{
------
This is regex to select functions from a C/C++ source and defined in... (2 Replies)
Discussion started by: alex_5161
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10. Shell Programming and Scripting
Experts -
I found a script on one of the servers that I work on and I need help understanding
one of the lines.
I know what the script does, but I'm having a hard time understanding the grouping.
Can someone help me with this?
Here's the script...
#!/usr/bin/perl
use strict;
use... (2 Replies)
Discussion started by: timj123
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GRCAT(1) General Commands Manual GRCAT(1)
NAME
grcat - read from standard input, colourise it and write to standard output
SYNOPSIS
grcat configuration
DESCRIPTION
configuration is a name of a configuration file. Directories ~/.grc/, /usr/local/share/grc/, /usr/share/grc/ are searched for the file (in
this order).
If the file is not found, it is assumed to be an absolute path of a configuration file located elsewhere.
Configuration file consists of entries, one per regexp, entries are separated with lines with first character non-alphanumeric (except #).
Lines beginning with # or empty lines are ignored.
Each entry consists of several lines. Each line has form: keyword=value where keyword is one of: regexp, colours, command, skip, count.
Only regexp is mandatory, but it does not have much sense by itself unless you specify at least a colour or command keyword as well.
regexp is the regular expression to match
colours is the list of colours, separated by commas (you can specify only one colour), each colour per one regexp group specified in reg-
exp.
command is command to be executed when regexp matches. Its output will be mixed with normal stdout, use redirectors ( >/dev/null) if you
want to supress it.
skip can be either yes, or no, if yes, the matched line will be skipped and not displayed in output. Default is no.
count is one of words: once, more, or stop.
once means that if the regexp is matched, its first occurrence is coloured and the program will continue with other regexp's.
more means that if there are multiple matches of the regexp in one line, all of them will be coloured.
stop means that the regexp will be coloured and program will move to the next line (i.e. ignoring other regexp's)
Regular expressions are evaluated from top to bottom, this allows nested and overlapped expressions. (e.g. you colour everything inside
parentheses with one colour, and if a following expression matches the text inside parentheses, it will be also coloured)
OPTIONS
None so far.
SEE ALSO
grc(1)
AUTHOR
Written by Radovan Garabik <garabik @ kassiopeia.juls.savba.sk>
GRCAT(1)