Questions tagged [regular-expression]
Regular expressions are a means of matching a pattern of characters within a string.
-1
votes
1answer
48 views
How to grep for a particular string?
I am trying to get a string that matches the following pattern: starts with foo and finishes with bar.
grep -e "^foo*bar$"
4
votes
3answers
260 views
Extract substring according to regexp with sed or grep
In a (BSD) UNIX environment, I would like to capture a specific substring using a regular expression.
Assume that the dmesg command output would include the following line:
pass2: <Marvell ...
1
vote
0answers
53 views
sed command is replacing the replaced text?
I am writing a bash script to rename icons. Specifically I am trying to change "icon-close-m" to "icon-close icon-size-medium" in HTML files. (though it could contain any substring besides "close", as ...
1
vote
1answer
34 views
Why is this regex not working in awk?
I have a text file as such:
Attribute 1.............. : attribute value
Encode Date............................. : JUL 2007
Attribute 22076.......... : attribute value`
I want to extract the JUL ...
0
votes
1answer
37 views
Multiple replacements using regular expressions in python
Can I use regex in python to have multiple types of substitutions? Like in this string "hello, this is me" I want to replace 'hello' with 'hi' and 'this' with 'its'.
Can I do it in a single line? Or ...
0
votes
1answer
22 views
How to specify regex quantifiers with mawk?
I'm familiar with the concept of specified bounded regex quantifiers as follows:
Quantifier Legend Example Sample Match
{3} Exactly three times \D{3} ABC
{2,4} ...
0
votes
2answers
44 views
Grep in bash issues
Sample string:
--000000000000f104a6057d4a0a10
Here I need to get for sure: "--"
Same files also contain a lot of similar strings; ------=_, --=_ , -----------, --< which currently also get ...
0
votes
2answers
24 views
split file lines by regex delimeter
I want to split each line from input file by a non-alphanumeric regex \W and print all the split chunks in the output file like so:
Input file:
www.wifi.in.ua
YI-HondBrychka
Output file:
www
wifi
...
0
votes
2answers
52 views
Can't replace my regex matches
I can filter files, I can can stream the matches of my regex ...
However, I need to remove exactly that, from a large file.
Regex:^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$
sed ...
0
votes
1answer
69 views
Regex expression for IP address/CIDR in bash
I want to check if the user input is a valid IP address/CIDR in bash and I am using regular expressions to do that. So valid CIDR should be 0-32 and for IP from (1-254).(1-255).(1-255).(1-255)/(1-32) ...
1
vote
2answers
94 views
How to mass rename files with regular expressions [closed]
I have a bunch of folders in a directory with files in them. Most of the filenames have region codes (retropie), and the scrubber will not match roms with single letter region codes (u,j,e,etc.). I ...
0
votes
4answers
88 views
grep IPs and port number into one line
Using grep and cut I have returned the IP and ports of the nmap scan result which looks like this:
192.168.1.221
80
443
192.168.1.223
25
Desired output:
192.168.1.221:80
192.168.1.221:443
192.168....
1
vote
2answers
44 views
grep for single back slash
I am trying to grep for the mount output to see the options for the root directory.
Why the following pattern (whitespace before and after a slash) is not working (with and without extended grep)
/...
2
votes
4answers
85 views
Removing (possibly nested) text quotes in command line
I need to parse large amounts text in command line and replace all (possibly nested) text quotes with spaces. Quotes are marked with specific syntax: [quote=username]quoted text[/quote].
Example ...
0
votes
0answers
29 views
Commenting out a specific host configuration in a Nagios configuration file
I have lots of Nagios configuration files like the one below in a directory, and I need to remove a host from monitoring.
define host{
host_name nmo
use aix-server
alias
hostgroups +...
1
vote
5answers
47 views
remove all lines with nullbytes/corrupt data
So I recovered a text file from an old hdd, but I failed to completely recover all of the data. The data that wasn't correctly recovered has returned as null bytes. How can I remove every line from ...
2
votes
2answers
41 views
how to find the real path of folder with regular expression
presto is distributed SQL query engine ,
and when we installed the presto then it should be created the following home folder
/application/DB/presto/presto-server-0.216
so we can say that
in ...
0
votes
1answer
43 views
Bash regex and IFS split
I have the following problem: I want to extract text that is inside brackets from a string (with or without the brackets). My string looks like this:
STR="[1] [2][345] [678 9] foo bar"
I initially ...
0
votes
0answers
44 views
Remove all words from a file except certain words
I have a file which represent a list of SQLs where caluses.
I want to remove everything that is not the columns names, and, or and where(case insensitive). In addition if it can also remove new lines ...
0
votes
1answer
57 views
sed: escaped square closing bracket does not match
Goal: replace  with <img src="url.png" alt="alttext">.
The ! and (...) parts work fine, it's the [...] part that I can't get to work.
As a simple example, I want to match ...
0
votes
2answers
82 views
Use FIND with MV to rename files. Delete the found string then prepending it to the filename?
find . -type f -name '*authors-name-string*' -exec bash -c 'mv "$0" "${0/authors-name-string/}"' {} \;
I am trying to rename files nested in several layers of directories that contain an author's ...
-1
votes
2answers
41 views
* in awk (metacharacters)
Can you explain me how * works?
I have an input:
U 8649 275 Asia
Canada 3852 25 North America
China 3705 1032 Asia
USA 3615 237 North America
India 1267 746 -Asia
...
4
votes
1answer
378 views
Awk - metacharacters
What is the difference between [+-] and [-+]. It seems to me doing the same thing. And what does [A-Za-z-]+ do?
Or I tried
awk '/[^-]/' contries
and I expected nothing as an output.
6
votes
4answers
398 views
Why does regex `“\.pdf”` match `/…/pdf…/…` in gawk, but not in mawk?
From How can I extract only the pid column and only the pathname column in the lsof output?
awk '{ for (i=9; i<=NF; i++) {
if ($i ~ "string" && $1 != "wineserv" && $5 == "REG" &...
1
vote
0answers
81 views
How to improve this 'sed' search & replace command?
How to search and replace recursively through multiple files in a directory, using essential tools installed in mostly any Debian/Ubuntu machine?
There are multiple answers in Stack* where to find ...
-1
votes
1answer
49 views
How to grep out all rows not matching the given pattern
I have csv files received on Linux, they come with their own different patterns, one example here:
$ head test.csv
wampproduct,wamp_date,wampregion,region_search_phrase,wamp,date_pull,end_of_month_dt
...
0
votes
1answer
52 views
Loop through many folders and do calculations with files with similar pattern in bash
I have several folders each containing several .nc files. I want to loop through all folders and for each folder do some calculations (mergetime) using cdo on files that have similar pattern. So far I ...
0
votes
3answers
85 views
Regex that matches this list of files?
I had a user on our shared host who let their Wordpress install fall victim of an exploit that allowed for arbitrary file creation as the apache user. The files generated are obviously generated with ...
11
votes
3answers
2k views
Correct regex not working in grep
I have this regex:
(?<=prefix).*$
which returns any character following string "prefix" and it works fine on any online regex engines (e.g. https://regex101.com). The problem is when I use that ...
0
votes
3answers
75 views
Modifying a shell variable with regex (bash)
I have a shell variable for example. a="big little man". How do I use regex in bash print out the variable with only the middle word capitalized? (big LITTLE man)
I can do it by separating the ...
2
votes
1answer
26 views
Using OR within regex pattern of grep [duplicate]
I use the following pattern for regex match in grep (zgrep, as searching within compressed files) as
zgrep -P '(?<=start).{20,120}(?=end)' *
I need to add some terms with OR operator in the ...
1
vote
2answers
68 views
RegEx Question on Linux - Sorting Date [closed]
It is possible to ignore some of the fields in an regex expression. The issue is that I have an output of a sorted files from an FTP server. The problem is that FTP does not list the year from the ...
2
votes
2answers
30 views
procmailrc-Killfile for recipient addresses?
I want to block mails with certain recipient addresses using procmailrc (temporary addresses that now only receive spam).
I found a code sample for using a killfile/blacklist, but it only applies to ...
0
votes
0answers
38 views
Change text color in PDF files
I want to change some Text-Coloring by regex search in one or more PDFs.
for example i want to change the color of all appearances of "A[0-9]+.[0-9]" like A120.1, A600.0 and so on.
is it even possible ...
0
votes
4answers
65 views
grep not working as expected
Given a file, "test.log" with the following contents:
line1 Patient 123 45566
line2 Patient 432
line3 Patient 234 456
line4 Patient 321
line5
I am trying to select line 2 and line 4 with this ...
0
votes
2answers
42 views
Batch rename a lot of file using a number find in filename
I have hundred of file name with a number tag in filename like this:
AAAA #12 SSSS.TXT
BBB #231 CDF.TXT
CDFSDAAAA #1 AAAASS.TXT
and i want to rename so:
#012 - AAAA #12 SSSS.TXT
#231 - BBB #231 CDF....
0
votes
2answers
89 views
Regular expression to remove all punctuation except commas in regex awk
I have a variable
local= "[ 'service center','New' ]"
I have used the following awk code to remove the square braces and single quotes,
local=gensub(/[\[\]']+/, "", "g", local);
Expected O/P ...
1
vote
2answers
124 views
Reading in variables from a file to use in a bash script strips out \
So I am loading in a properties file to define some variables. In this example imagine it is a string mark!slash\ending\ called INPUT.
INPUT is declared by loading in the properties file using:
. ./...
1
vote
1answer
39 views
sed - why this script is incorrect
I'm reading the RegEx chapter in Classic Shell Scripting and types the example code.
Here is the command: which changes the path "/home/tolstoy" to "/home/lt".
$ echo /home/tolstoy | sed 's;\(/home\)...
2
votes
1answer
274 views
Regex search list of emails
So I have a long list of email and I want to search these based on just a few sections of the email string.
I want to try and search these emails more efficently so I want to match the start of the ...
0
votes
2answers
60 views
How can sed replace in the range of nth line regex specified?
I am to replace using sed the 3th (or nth to be more general) occurrence in respective line with specified match regex.
so far as i can is only to do the first:
$cat file
# Golden dictionary is a ...
1
vote
0answers
52 views
I need to search ps output for a match and then recursively for a second match [closed]
I need to find two matches in the output from ps. I am searching with ps -ef |grep mysql for:
/bin/sh /usr/bin/mysqld_safe --defaults-file=/data/mysql/master/agis_core/etc/my.cnf
after this match ...
2
votes
1answer
41 views
Replacing bad file, directory and subdirectory names using a regex pattern
I have a bunch of directory, sub-directory, and filenames that were created in Linux with the following pattern: YYYY - MM - DD T HH : MM : SS (I added spaces for clarity but no spaces are in the ...
2
votes
2answers
429 views
How can I do an “or” search with find? [duplicate]
Essentially, I want to know how to run 2 (or more) find commands in one - an "or" search rather than an "and":
find . -name "*.pem"
find . -name "*.crt"
0
votes
3answers
81 views
Non-greedy matching in sed [closed]
In a bash script, I have the following variable:
file_name='this_is_the_hart_part.csv'
Using
var2=$(echo $file_name | sed -e 's/_{2}\(.*\)_{3}/\1/')
I want to extract the substring "the" (between ...
-1
votes
2answers
71 views
grep pattern next two lines and discard the pattern with one line
I have a file something like this:
dn: danan
cn: danian
cn: danian1
dn: danian2
cn: danian2
dn: danian3
cn: danian3
cn: danian4
all I want to do is grep the pattern "dn:" and print just the ...
0
votes
1answer
45 views
What are Interval Regular Expression and Tagged Regular Expression?
I was recently reading about sed when I encountered this topic. I need examples to understand the topic better.
-1
votes
1answer
31 views
how to capture details from nc
by the following command we can identify which ip are using port 2181 and the relevant port
echo stat | nc localhost 2181
Zookeeper version: 3.4.6-91--1, built on 01/04/2018 10:34 GMT
Clients:
/182....
0
votes
0answers
36 views
How can I regex match-and-replace _all_ on-screen text?
I need a way to replace an on-screen pattern with another string, regardless of what places that text on the screen. Maybe I can live without user input being replaced, but anything that comes from ...
1
vote
3answers
93 views
Can't run parallel zgrep with regex
When I run this:
find . -name "my.log*.gz" -print | \
parallel zgrep -e "\(text1\|text2\).*Exception"
to find all lines that match /(text1|text2).*Exception/ in all files in the folder, I get this ...
