Questions tagged [regex]
Regex (or regexp) is known as regular expression matching of patterns, strings or characters in, for example, a large text file. Questions should be tagged as such whatever the programming language involved and the tag can also apply to command-line or graphical programs that have regex plugins or some regex capability.
307
questions
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Perl: replace literal expression and literal variable names
When I use this expression:
echo '...${var}#other.([]);,=${var}#other${var}...' | perl -pe 's/\Q.([]);,=${var}\E/.([]);,=ok/'
As expected, the variable ${var} is expanded to "" (empty value)...
- 157
1
vote
1
answer
53
views
What regex flavor does gedit support?
On Ubuntu 20.04, my version of gedit 3.36.2 came with a regex checkbox for Find and Replace out of the box without installing any plugins. Which regex flavor is used?
- 2,702
1
vote
1
answer
53
views
grep PCRE still greedy
I'm searching a multi-line text file and want to match a string from a certain word until the first match of another word:
start
word1
word1
word1
word1
end
word2
word2
word2
start
word3
word3
word3
...
- 13
2
votes
2
answers
478
views
bash: syntax error near unexpected token '|'
Once logged in, use the "Find" utility to search within the current folder for the file whose name matches the following regex pattern:
lower-case letter
number
special character (% & # ...
0
votes
1
answer
63
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How to extract channel names from YouTube subscription source file
I have an html source file of YouTube subscriptions, and want to extract just the /user/CHANNELNAME parts into a separate file.
The source file (browser > youtube.com > subscriptions > manage ...
- 3,942
0
votes
2
answers
72
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why grep with regex command not working on Ubuntu
I wanted to know the packages which are installed and starting with mos then below command not working.
dpkg -l | grep ^mos*
- 6,475
0
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1
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65
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Does grep and friends have a way to match strings as if shell file name globbing in stead of regex
Effectively I'm trying to search a text file containing "file names" and want to match as if shell file globbing were in effect.
Shell file globbing is much simpler than regular expressions, ...
0
votes
1
answer
56
views
Remove characters from file name - between [ and ]
i download videos from YouTube for my hobby. The filenames contain some random characters between the [ and ]. E.g. filename [vbnghztresku].webm.
My partial solution starts as follows:
find /medien -...
- 1
0
votes
0
answers
98
views
Foremost (data recovery) placing output in hidden directory, cannot be located
There is an issue with the foremost software that prevents it from reading location names with spaces. In these instances, it simply ignores the specified location and places the output in some ...
- 21
2
votes
1
answer
275
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Why "mount | grep sdb" displays no output, when "sdb" drive is a [swap] partition?
I'm learning about lsblk and mount commands in Ubuntu.
I'm using Linode vps server, 2CPU, 4GB ram with 1 additional block storage volume attached.
I have 2 questions related with this subject.
At ...
- 175
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votes
1
answer
135
views
End of line in sed command
I need to append some variable string at the end of every line in the file using the sed command.
Let's say that $var is a variable string.
If I use a single quote sed -i 's/$/$var/' inputfile.txt --&...
0
votes
1
answer
220
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Can globbing be used to search file contents?
I basically understand that globbing is used for filename expansion in the shell. I also understand that regular expressions are used for text pattern matching within a file. However, is globbing also ...
- 139
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1
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15
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Need help to figure out a regex to modify some files
I have some files that I need to clean up some names.
for example:
GCA_940670685.1_Clostridium_sp_chr 3757330
GCA_940677205.1_Clostridium_colinum_chr 2035557
GCA_942548115.1_Aeromicrobium_sp_chr ...
0
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0
answers
83
views
I am looking for a text editor allowing to save and edit a list of search and replace expressions (search in multiple files, a plus)
I am looking for a text editor for linux (I am using Ubuntu) that is able to save, let me edit and choose among a list of search and replace list. I have looked around and cannot find what I am ...
- 11
0
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2
answers
85
views
Rename files matching expression
I have to rename a lot of jpg files like Portrait_14-9-100390.jpg to Portrait-9-100390.jpg,i.e. remove _nn part.
I did that with a dumb shell script :
sudo rename -f -v 's/_20//' /var/www/prod/110253/...
0
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1
answer
122
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Krusader quick search on Ubuntu 20.04 : What syntax to use to search for filenames with RegEx?
Installed Krusader on Ubuntu 20.04 as Nautilus dropped sorting of search results.
Cant find a way (syntax) to do a QuickSearch with RegEx; I know how to write RegEx syntax, but what special character(...
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0
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1
answer
142
views
multitail regex not working
I am trying to use multitail to colorize some log files for a program I have written. I've created my own colorscheme within /etc/multitail.conf and I am able to colorize a very simple regex that ...
-3
votes
1
answer
110
views
Pattern that is not a negative integer
In bash, I can use Posix Character Class such as
digit="[[:digit:]]"
There are also
[[:alnum:]], [[:alpha:]], [[:ascii:]], [[:punct:]]
What pattern can I use to match something that starts ...
- 361
0
votes
1
answer
114
views
Search snaps using regex/patterns
Is it possible to narrow down the results of snap find <package>? For example, if I search for code as:
snap find code
can I add another keyword that should be looked at in publisher or summery?
...
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0
votes
1
answer
69
views
Bash script to automate codec installation
I recently moved from Ubuntu 20.04 to 22.04. I don't keep any media files but when I visited youtube I discovered no audio was playing. After some time I came to (guided)conclusion that I need to ...
- 1
1
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1
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2k
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How to validate a domain name with regex Bash script?
I'm trying to validate any domain name but it seems doesn't work the match. Don't understand why the syntax looks fine and I also verified this regex on https://rubular.com/r/QmX59URV8D
It's working ...
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0
votes
3
answers
105
views
While $value != [a..b]
I'm trying to write a function that rewrites a value according to a user's choice. So far it looks like this:
while [[ $code_id != [1-28] ]]; do
echo "Please select a value..."
echo "1. ...
- 9
0
votes
0
answers
884
views
rsync pattern to include all files of specific patterns and exclude the rest, from all subdirectory tree
I mean to rsync some files of a subdirectory tree at dir1.
I am using
[dir1]$ rsync --itemize-changes --recursive --update --times --include-from="rsync_include.dat" --exclude="*" -...
0
votes
1
answer
120
views
How to save specific lines of command line outputs
I have an executable that produces the following to the terminal:
---Start---
Some text
More text
-1.
1.
0.39
10
-199
some more text
Complete
---End---
I want to write only the numerical values in ...
- 101
1
vote
0
answers
34
views
Is it possible to restrict a regular expression to a given number of characters or perform two logically AND connected tests in one regex?
I have to split a table into columns.
The texts in two neighboring columns each match the expression (\S+\s+)+\s*. But sometimes, one column gets a bit larger than it should and then there is only one ...
- 613
1
vote
2
answers
2k
views
In arbitrary line of text, how can bash extract a named value after an equal sign?
This question (How to get values after an equal sign) is basically what I want:
Given a line of text, with named parameter looking syntax like color=red, using bash how can you grab that color value (...
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-2
votes
1
answer
194
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match all the items that i have enough of to afford. simple regex
Taking a self guided linux tutorial and I keep getting hung up on this
My output keeps including the "clock 15" please help
#!/bin/sh
#comment single RegEx to match all of the items that you ...
0
votes
1
answer
84
views
LibreOffice: indent all lines starting with italic via find/replace
I have a huge text, and I would like to indent all lines which start with italic text, via find/replace.
I tried using ^ and italic via the format button, but then the search string is not found.
If I ...
- 1
0
votes
1
answer
527
views
Regex to match lines that access a certain port and particular packets
New to Linux and the only way I can get this to work is by using the awk command unfortunately the main directions specify to not use awk.
this is what I got
#!/bin/sh
#comment Write a single RegEx to ...
0
votes
1
answer
135
views
Rename using both captured groups and other variables
In this question I understood that we can only refer to captured groups in the rename command using single quotes.
Is there a way to use both captured groups and other variables in the same rename ...
0
votes
1
answer
72
views
when using ?!<string> in perl regex, bash interprets it as search through command history
Simple problem but I can't fix it.
I have the following perl regex:
echo ... | grep -P "(?i)(v(ersion)?)\s?(?!0)\d(\.|,)\d{1,}"
This is supposed to match every string that describes a ...
- 562
0
votes
1
answer
2k
views
When piping grep after a curl request, regex works very strange
Simple problem but really weird.
When I make a curl request and do ... | grep -Po "^\d+$", it returns nothing eventhough there are 400+ results that should match. See below:
#example snippet ...
- 562
5
votes
1
answer
1k
views
Remove and replace all Slashes from Filenames recursively
I want to rename every File in a folder-subsystem that contains a slash to be replaced with an underscore
Current filenames example:
Hello/there.txt
File/name.jpg
to
Hello_there.txt
File_name.jpg
...
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0
votes
1
answer
198
views
Itemized Meaning of the RegEx: "(/.*)?"
I am trying to determine each element of this regular expression:
"(/.*)?"
Here is what I have learned on my own so far:
() == grouping regex together
/ == ???
. == equal to any one ...
0
votes
0
answers
42
views
batch renaming all files in a folder to lowercase letters regex not working [duplicate]
I need to rename all folders and files to lowercase, I looked on this forum and found the following command
find . -name * -type f -exec rename 'y/A-Z/a-z/' '{}' \;
I tried this, and while the ...
2
votes
2
answers
3k
views
replace text with part of text using regex with bash perl
For example I have this output:
string1 anynameveryveryverylong string2
string1 othernameveryveryverylong string2
I want truncate the name to the first ten characters:
string1 anynamever string2
...
- 157
0
votes
0
answers
37
views
A lot of errors while reinstalling MongoDB [duplicate]
I can't use MongoDB so I need to uninstall, but when I try to reinstall it, the program shows me a lot of errors in MongoDB, MySQL and also in dpkg.
sudo apt-get purge mongodb-org*
Reading package ...
3
votes
3
answers
208
views
bash perl \z doesn't work
I have this text file or sdout:
text1
text2
text1
text2
text1
text2
I have this code:
perl -pe "s/text2\n\z/text3/s" text.txt #Note the modifier "/s"
I with \z expect him to ...
- 157
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votes
2
answers
141
views
Bash command to recognize difference between variables
I am given from stdin 2 variables a name and a number given in any order. How can I identify them correctly in a bash script such that I can print them in a file in the same order(age, Name)
./a.sh ...
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0
votes
1
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274
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ignore python cache in Unison: ignore Path */__pycache__
Is
ignore Path */__pycache__
the correct approach to ignore all python cache files from being synced with Unison?
I do so by adding Path */__pycache__ in the graphical user interface.
I know very ...
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3
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127
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Re: How can I escape meta-characters when I interpolate a variable in Perl's match operator?
The link
How can I escape meta-characters when I interpolate a variable in Perl's match operator?
didn't help me.
I have tried with Python:
import os
line='ID_SN=02 MS=DC:A6:32:7E:74:08 S=* ...
- 157
0
votes
0
answers
44
views
matching single and double quotes in grep using -E [duplicate]
For practicing how grep works in Ubuntu terminal, I made one .txt file:
'"..asdf_-_-..34'""'"'"
jd8m***ns'''_**''x;';nn*?/...;
++..++
./,/;]_+))(+_)((*+_":|.<"{}...
0
votes
1
answer
122
views
bash perl "and" operator
with a output:
apple text1
peach text2
banana text3
melon text4
For delete rows that begin with "apple" or "banana" i put:
perl -pe 's/^apple.*\n|^banana.*\n//g'
And output is ...
- 157
4
votes
2
answers
918
views
bash --> perl command: print only the replaced text
I have the file "test.txt" that contains:
Val1 = '59'
Val2 = '76'
Val3 = '42'
Val4 = '53'
I with this command:
perl -pe "s/^Val2 = '(.*)'/\1/" test.txt
I Want:
76
But I obtain:
...
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0
votes
1
answer
348
views
Geany find and replace characters with accent
I use Geany editor for some time, and find it very useful.
However, I cannot manage to find an efficient way to replace all characters which have accents in a single action:
Rubén, Éliot y el niño =&...
- 441
0
votes
0
answers
29
views
grep regular expression to remove packages [duplicate]
This is an unexpected result I get
$ dpkg -l | grep linux-modules-nvidia-440-5.4.0-*
rc linux-modules-nvidia-440-5.4.0-26-generic 5.4.0-26.30+2 amd64 ...
1
vote
1
answer
5k
views
Does grep distinguish a variable and the $ regex?
I want to grep for a variable that has the string test, but I also want to make sure that it will only find test if that is the only word on a line.
So, I tried this:
string=test
echo "test" ...
- 650
1
vote
2
answers
112
views
How to sort only usb keys?
I'm on Ubuntu 20.04
what if i want to sort only the usb keys to have an output that would be like this.
usb key name / size Gb / path to the usb key
I tried this but I have both the hard drives and ...
- 13
1
vote
1
answer
523
views
How to escape backticks in a .bash_aliases file?
How do I escape backticks as below:
root:~#
root:~# cat .bash_aliases
alias clean='docker rm `docker ps -aq`'
root:~#
see also:
https://stackoverflow.com/q/1250079/4531180
and
https://...
- 1,064
0
votes
1
answer
323
views
sed with parens in seach not working
I need to replace
DatabaseConnection.GetConnection()
with
DatabaseConnection.GetConnection(_connectionString)
Using grep (GNU grep) 3.1
grep GetConnection() CustomerRepository.cs
yields
bash: syntax ...
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