Questions tagged [regex]
When asking regex questions, always add the tag for the specific programming language or tool (e.g., Perl, Python, or Java; vi, emacs, or ɢɴᴜ grep; etc.) you are using.
730
questions
67
votes
2
answers
106k
views
Nginx location regex doesn't work with proxy pass
I'm trying to get these 2 location directives working in Nginx but I'm getting some errors back when booting Nginx.
location ~ ^/smx/(test|production) {
proxy_pass http://localhost:8181/...
- 821
43
votes
2
answers
151k
views
Nginx: location regex for multiple paths
I have two locations in nginx config that work:
location ^~ /media/ {
proxy_pass http://backend.example.com;
}
location ^~ /static/ {
proxy_pass http://backend.example.com;
}
How can I combine ...
- 565
40
votes
5
answers
100k
views
Using sed to remove both an opening and closing square bracket around a string
I'm running this command in a bash shell on Ubuntu 12.04.1 LTS. I'm attempting to remove both the [ and ] characters in one fell swoop, i.e. without having to pipe to sed a second time.
I know square ...
- 1,052
31
votes
7
answers
90k
views
Don't need the whole line, just the match from regular expression
I simply need to get the match from a regular expression:
$ cat myfile.txt | SOMETHING_HERE "/(\w).+/"
The output has to be only what was matched, inside the parenthesis.
Don't think I can use grep ...
- 591
31
votes
2
answers
199k
views
Nginx wildcard/regex in location path
The Nginx config I have throws 404 for .php like:
## Any other attempt to access PHP files returns a 404.
location ~* ^.+\.php$ {
return 404;
}
However I have some index.php file in subfolder ...
user156477
21
votes
10
answers
23k
views
Extract repository name from GitHub url in bash
Given ANY GitHub repository url string like:
git://github.com/some-user/my-repo.git
or
[email protected]:some-user/my-repo.git
or
https://github.com/some-user/my-repo.git
What is the best way in ...
github
20
votes
2
answers
25k
views
What is the difference between Nginx ~ and ~* regexes?
What is the difference between Nginx ~ and ~* regexes?
For example:
if ($http_referer ~* www.foobar.net) {
...
}
vs
if ($http_referer ~ www.foobar.net) {
...
}
- 302
20
votes
2
answers
40k
views
NGINX Proxy_Pass remove url substring
I have one NGINX acting as reverse proxy. I need to remove a substring string_1 from the URL, the rest of the URL is variable.
Example:
Origin: http://host:port/string_1/string_X/command?xxxxx
...
- 677
19
votes
3
answers
66k
views
How do I match a wildcard host in ACL lists in HAproxy?
I have the following lines in my haproxy.conf:
acl valid_domains hdr(Host) -i mysite.com images.mysite.com docs.mysite.com admin.mysite.com
redirect location http://mysite.com/invalid_domain if !...
- 731
19
votes
1
answer
573
views
Why bracket a single letter in a grep regex?
I've seen several instances where people are doing this:
grep [f]oobar
But I don't understand why that is preferable to
grep foobar
- 565
16
votes
6
answers
16k
views
Modify fail2ban failregex to match failed public key authentications via ssh
fail2ban doesn't recognize failed public key ssh logins and I assume that this can be solved by modifying the failregex of /etc/fail2ban/filter.d/sshd.config to match the following line:
<date> ...
- 263
16
votes
1
answer
8k
views
Ack search for literal strings [closed]
I am sick of having to escape things when I want to search for part of an html tag.
How can I ack search for exactly what I type without having to escape stuff?
e.g.
ack-grep 'console.log(foo'
I ...
- 565
15
votes
4
answers
63k
views
nginx rule - match all paths except one
I am trying to match all paths that begin with /newsletter/ except one (/newsletter/one) with a regex.
What I have so far:
location ~ ^/newsletter/(.*)$ {
// configuration here
}
This matches all ...
- 433
14
votes
1
answer
8k
views
nginx pcre_compile error when using quantifiers
I'm having an issue with aliasing. I want to append up to the first 4 digits of the file as part of the directory. (like '../123456.jpg'=>'../123/123456.jpg' and '../12.png'=>'../12/12.png')
Here is ...
14
votes
2
answers
23k
views
What are PCRE limits?
In ModSecurity there are PCRE limits exceeded errors.
I know I can fix this by setting rules such as:
SecPcreMatchLimit 150000
SecPcreMatchLimitRecursion 150000
But, what are these rules actually ...
user101130
13
votes
7
answers
30k
views
Renaming files in linux with a regex
I had a group of files that I'd like to consistently rename, the files are named things like
"System-Log-01-01-2009-NODATA.txt"
"Something-Log-01-01-2009-NODATA.txt"
And I wanted them as lowercase, ...
- 824
13
votes
2
answers
13k
views
Grepping for CIDR ranges
From time to time I want to grep CIDR ranges out of my Apache log files. This is easy for ranges that fall on the natural boundaries (/8, /16 and /24) but not so easy for other ranges such as /17 and ...
- 26.6k
13
votes
3
answers
51k
views
nginx rewrite append a parameter at the end of an url
I need to configure my reverse proxy so that the following parameter will be added at the end of the url: &locale=de-de
This almost works:
rewrite ^(.*)$ $1&locale=de-de break;
However, the ...
- 538
13
votes
1
answer
8k
views
Why is it unnecessary to escape "/" in Nginx regular expressions?
So I've made it a thing to finally learn about regular expressions. Normally when working with regular expressions it is necessary to escape delimiters (like "/") with a "\". But when I'm using ...
- 279
13
votes
1
answer
348
views
How do I make sec ignore a timestamp properly
I have a rule that is set up like so;
In /etc/sec/rules.d I have;
type=SingleWithSuppress
ptype=regexp
pattern=(\S+) sshd\[\d+\]: PAM \d+ more authentication failures\; logname=.* uid=.* euid=.* tty=...
- 2,052
11
votes
2
answers
41k
views
nginx simple regex location
I need to set a location param in nginx if the first 5 digits of the url are numbers.
site.com/12345/ or site.com/12345
But I can't for the life of me seem to get the correct regular expression.
...
11
votes
1
answer
18k
views
Nginx redirect all old domain subdomains to new one
I had a very long domain, so I decided to change it to a shorter and more friendly one. But since I have a lot of subdomains (in fact, I have a subdomain wildcard), I wanted to keep the subdomain ...
- 233
11
votes
2
answers
20k
views
How to exclude files from TAR archive using regular expressions?
I have a simple question, yet I can't find or solve the answer. I want to make a tar archive, but I want to exclude some files from it using regular expression.
Example of the file to exclude is this:...
- 273
10
votes
5
answers
156k
views
Most simple way of extracting substring in Unix shell?
What's the most simple way to extract substring on Unix shell (with regex)?
Simple means:
less feature
less options
less study
Update
I realized regex itself is conflicting with simplicity, and I ...
- 10.6k
10
votes
2
answers
11k
views
How can I route some emails to a script in Postfix?
How do I route all emails directed to user-*@example.com (i.e. [email protected]) to a pipe command in Postfix? The idea is to create craigslist-style anonymization by assigning dynamic email ...
- 203
10
votes
1
answer
25k
views
Nginx proxy_pass root and specific url only
Working on a new version of an existing web app, I need nginx to forward root (/) and multiple specific URI to be forwarded to the v2 infrastructure (with proxy_pass) while not specified URI must be ...
- 325
9
votes
3
answers
9k
views
rsync: How to exclude Dotfiles only in topmost directory?
When performing backups under Bash with rsync, I'm trying to exclude all dotfiles and hidden directories in the top directory, but not those in otherwise targeted directories. For example:
/copyme.c ...
user937189
9
votes
1
answer
16k
views
Show real server name in nginx logs and params passed to fastcgi?
I have configured my nginx vhosts with a regex in server_name. nginx shows the raw regex in logs and in params passed to php-fpm (I know there's $_SERVER['HTTP_HOST'] with a real value, that's not an ...
- 91
9
votes
4
answers
6k
views
Searching for literal "> \" using ack-grep
I am looking for lines that literally have a greater than character (a ">") followed by a space followed by a backslash character (a "\")
i.e., a line with this: > \
I thought escaping would allow ...
- 261
8
votes
1
answer
63k
views
Extracting part of the string using Ansible regex_search and save the output as a variable
I'm having a content like below inside a file.
dataDir=/var/lib/zookeeper
4lw.commands.whitelist=mntr,conf,ruok,stat
syncLimit=2
I wanted to read the value for dataDir using Ansible and set it to a ...
- 213
8
votes
4
answers
36k
views
nginx rewrite base url
I would like the root url
http://www.example.com
to redirect to
http://www.example.com/something/else
This is because some weird WP plugin always sets a cookie on the base url, which doesn't let ...
- 125
7
votes
2
answers
5k
views
Why does this regex not work on linux?
I can't say it works on Windows but from my understanding this regex is correct and how I would write it (except maybe the ^ at the beginning)
From http://www.velocityreviews.com/forums/showpost.php?...
user274
7
votes
1
answer
19k
views
How do I format this regex so it will work in fail2ban?
I've just installed fail2ban on my CentOS server in response to an SSH brute force attempt. The default regular expressions in fail2ban's sshd.conf file do not match any entries in audit.log, which ...
- 181
7
votes
6
answers
3k
views
Globally Coloring the Terminal by Regex
I know many programs use color - (vim, ack, color-ls to name a few) but there are still many cases where you're stuck with black and white.
There are scripts that will color output based on regular ...
- 293
7
votes
2
answers
18k
views
nginx url rewriting. i just don't get it
Ok, an example url is
http://www.mysite.com/?p=account&view=settings
the p uri is a constant. all urls have it.
the view is one of many optional uri.
i've tried to understand url rewriting ...
- 202
7
votes
4
answers
11k
views
nginx error log Grok pattern
I am having trouble getting the following nginx error log message to parse in the grok debugger. I have a feeling there is a stupid trick that I should use but can't figure out what it may be.
...
- 790
7
votes
1
answer
193
views
Is there a tool that can top-ify an input stream?
I come across quite a few use cases where it would be very useful to take input from a (usually newline-delimited) stream and summarise it in a top-like fashion (see top, iotop, etc). A kind of on-...
- 1,825
6
votes
7
answers
52k
views
Copy multiple folders to a single destination with robocopy
I'm looking for a solution to use robocopy to copy several folders from a directory onto a distant network share. I want to choose several folders out of a directory that contains hundreds of folders ...
- 228
6
votes
2
answers
8k
views
Regex negative look-ahead is not working for mod_rewrite between different Apache versions
I have a mod_rewrite line that works under Apache 2.2, but not under Apache 1.3:
RewriteRule ^(?!index.php)(?!skin/)(?!js/)(.+) /index.php?file=$1 [NC,L]
If I lose the negative ...
- 193
6
votes
1
answer
12k
views
apt-get install packages matching wildcards
I am running Debian 8 Jessie, trying to install PHP command line intepreter from a shell script.
Here is what I do:
sudo apt-get install php-cli
it tells me there is no php-cli. I do find there is ...
- 195
6
votes
5
answers
13k
views
apache locationmatch negative regex
I'm trying to expose a location through Apache. Normally, I have this block in my vhost that says
<Location />
AuthType Basic
AuthUserFile /web/.htpasswd
AuthName "Test Site"
...
- 61
6
votes
1
answer
657
views
I can not seem to get a Regex for to Fail2Ban to work with Opensmtpd? Can I get a sanity check?
I have openSMPTD running a mail server. It seems I am getting brute forced attacked currently, although I doubt they will get in. That being said, I would like to alleviate the burden on my server ...
- 179
6
votes
1
answer
4k
views
nginx regex characters that require quoting?
So I was configuring nginx today and I hit a weird problem. I was trying to match a location like this:
location ~ ^/([0-9]+)/(.*) {
# do proxy redirects
}
...for URLs like "http://my.domain.com/...
5
votes
3
answers
2k
views
Bash command for regular expression substitution
What bash command can be used for regex substitution on a pipe?
cat foo.txt | someprogram
- 2,387
5
votes
1
answer
7k
views
Regex for multiple sshd Received disconnect from ... [preauth]
What fail2ban regex would catch logs like these?
Apr 9 08:48:28 server sshd[1856]: Received disconnect from 43.255.190.117: 11: [preauth]
Apr 9 09:06:05 server sshd[1936]: Received disconnect ...
- 161
5
votes
1
answer
17k
views
Regular expressions in server_name with Nginx vhost
I have something I'm trying to do with Nginx. Say I have a few users and a subdomain, and each user has a directory at /home/dev/sites/USER_ID. I would like for USER_ID.dev.example.com to point to ...
- 152
5
votes
3
answers
22k
views
Regex for sed to grab multiple lines or a better way?
I'm creating a script that connects to a server and dumps the output to a tempfile. I want to use sed in the script to grab specific information from the temp file. The output would always have the 80 ...
- 387
5
votes
2
answers
4k
views
fail2ban find matches, but does not ban
I am using fail2ban 0.9.7 on CentOS 7 along with an Apache reverse proxy, trying to ban bots trying to access my server as an open proxy, such as :
221.8.179.164 - - [10/Jun/2019:22:04:19 +0200] "...
- 61
5
votes
2
answers
5k
views
Is it possible to get the matched regex from within the apache LocationMatch directive?
I'm wondering if the following code should be working:
<LocationMatch "/(.*)([/])?(.*)">
Order allow,deny
Allow from all
AuthType Basic
AuthName "Git"
AuthUserFile /git/....
- 1,508
5
votes
1
answer
2k
views
NGINX: map and try_files not working
i am using nginx to detect webp support in browser:
# Check if client is capable of handling webp
map $http_accept $webp_suffix {
default "";
"~*webp" ".webp&...
- 143