FWIW: The standards issues with regex are something that that appears to be coming together well. Or better anyway.
Basically when you are using UNIX tools, IMO, regex use has this sort of feel to it:
This is the way UNIX was overall back in the 90's - XOPEN, SUS, SVID, SYSV, BSD, Torvalds etc.
Henry Spencer ( zoologist) wrote the first open source version of UNIX regex, which then allowed the creation of cascade of modern regex "flavors". Larry Wall appears to have used Spencer's regex as a model for perl regex, for example.
So, if you understand the difference between extended regular expressions (ERE) and basic (BRE) you are well on the way.... to Belgium.
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)
I have these two files in current dir:
oos.txt
oos_(copy).txt
I execute this find command:find . -regex './oos*.txt'And this outputs only the first file (oos.txt)! :confused:
Only if I add another asterisk to the find find . -regex './oos*.*txt' do I also get the second file... (7 Replies)
Hi,
Please help me to understand the bold segments in the below regex.
Both are of same type whose meaning I am looking for.
find . \( -iregex './\{6,10\}./src' \) -type d -maxdepth 2
Output:
./20111210.0/src
In continuation to above:
sed -e 's|./\(*.\{1,3\}\).*|\1|g'
Output: ... (4 Replies)
I have the following line of code that works wonders. I just don't completely understand it as I am just starting to learn regex. Can you help me understand exactly what is happening here?
find . -type f | grep -v '^\.$' | sed 's!\.\/!!' (4 Replies)
Hi Guys,
Could you please kindly explain what exactly the below SED command will do ?
I am quite confused and i assumed that,
sed 's/*$/ /'
1. It will remove tab and extra spaces .. with single space.
The issue is if it is removing tab then it should be Î right ..
please assist.... (3 Replies)
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)
Hi everyone,
This regex looks simple and yet it doesn't make sense how it's manipulating the output.
ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0c:49:c2:35:6v
inet addr:192.16.1.1 Bcast:192.168.226.255 Mask:255.255.255.0
inet6 addr:... (2 Replies)
I'm trying to get some exclusions into our sendmail regular expression for the K command. The following configuration & regex works:
LOCAL_CONFIG
#
Kcheckaddress regex -a@MATCH
+<@+?\.++?\.(us|info|to|br|bid|cn|ru)
LOCAL_RULESETS
SLocal_check_mail
# check address against various regex... (0 Replies)
Hi,
I need some guidance with understanding this Perl script below. I am not the author of the script and the author has not leave any documentation. I supposed it is meant to be 'easy' if you're a Perl or regex guru. I am having problem understanding what regex to use :confused: The script does... (3 Replies)
Hello All,
While googling on regex I came across a site named Regulex Regulex:JavaScript Regular Expression Visualizer
I have written a simple regex ^(a|b|c)(*)@(.*) and could see its visualization; one could export it too, following is the screen shot.
... (3 Replies)
Discussion started by: RavinderSingh13
3 Replies
LEARN ABOUT PHP
re_comp
RE_COMP(3) Linux Programmer's Manual RE_COMP(3)NAME
re_comp, re_exec - BSD regex functions
SYNOPSIS
#define _REGEX_RE_COMP
#include <sys/types.h>
#include <regex.h>
char *re_comp(const char *regex);
int re_exec(const char *string);
DESCRIPTION
re_comp() is used to compile the null-terminated regular expression pointed to by regex. The compiled pattern occupies a static area, the
pattern buffer, which is overwritten by subsequent use of re_comp(). If regex is NULL, no operation is performed and the pattern buffer's
contents are not altered.
re_exec() is used to assess whether the null-terminated string pointed to by string matches the previously compiled regex.
RETURN VALUE
re_comp() returns NULL on successful compilation of regex otherwise it returns a pointer to an appropriate error message.
re_exec() returns 1 for a successful match, zero for failure.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
+---------------------+---------------+-----------+
|Interface | Attribute | Value |
+---------------------+---------------+-----------+
|re_comp(), re_exec() | Thread safety | MT-Unsafe |
+---------------------+---------------+-----------+
CONFORMING TO
4.3BSD.
NOTES
These functions are obsolete; the functions documented in regcomp(3) should be used instead.
SEE ALSO regcomp(3), regex(7), GNU regex manual
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
GNU 2017-09-15 RE_COMP(3)