Questions tagged [perl]
Perl is a high-level, general-purpose, interpreted, dynamic programming language. It was originally developed by Larry Wall as a general-purpose Unix scripting language to make report processing easier, over a period with support from open source community, it has evolved and matured to be used for graphics programming, system administration, network programming, finance, bioinformatics, and other engineering applications.
1,364
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Problem enabling perl module stream AlmaLinux 8.10
I have an issue with our AlmaLinux 8.10 systems that they suddenly have issues with perl dependancies. It tuns out that the current active perl stream is 5.26 (dnf module list perl*) but some packages ...
-1
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3
answers
90
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Delete 2-line paragraphs, keep 3-line paragraphs, maintain newline between all
On a Linux machine with GNU tools I have an ascii file that consists of only 2-line and 3-line paragraphs, each paragraph separated by a newline. All 2-line paragraphs are to be deleted so that all 3-...
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1
answer
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version `XCRYPT_2.0' not found after Update Debian 10 to Debian 12
I was instructed to upgrade Debian 10 to Debian 12. After the upgrade, I noticed that the ssh.service was not working. Now I found out that no 'apt' commands work. I can't install anything.
Here the ...
16
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5
answers
1k
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How can UserA programmatically replace a text string within a file they own that's located in /etc?
A non-root linux user owns a text file that's located in /etc, where the non-root linux user does not have permission to create files. The non-root linux user can edit the file manually via vi without ...
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1
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What does the line ($eachJOBID = $eachScriptNoPath) =~ s/\.csh// ; do?
This line I have in my code cuts the .csh from a string and returns the rest of it. Can someone explain what each part of it does?
($eachJOBID = $eachScriptNoPath) =~ s/\.csh// ;
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3
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73
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Bash: sum a number present in N lines before a given pattern
I have a kdenlive project file (which is basically a xml file) with a lot of text clips inside. I need to bulk edit the x coordinate of a certain text that appears multiple times. This is an example:
...
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3
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1
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472
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Why is one process ps command showing spaces around a directory instead of slashes?
I'm trying to debug a failing legacy process monitor that searches processes that are running. I determined it is being caused by some mysterious linux behavior. The process being ran is /opt/my/path/...
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1
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1
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how to catch output from a subprocess?
I am trying to catch the password prompt of sftp, but somehow it is not from STDIN or STDERR. It possibly comes from a sub-process.
The following is my test. I tried to redirect the password prompt to ...
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1
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AWStats stuck, but no output on strace: How to debug?
A Perl script is stuck,
root 1317478 99.8 0.0 264072 22516 ? R 04:57 478:37 /usr/bin/perl /usr/share/awstats/wwwroot/cgi-bin/awstats.pl -config=domain.tld-http -staticlinks -configdir=/...
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3
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644
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awk: sort by first column then second; output unique 1st column once but all 2nd column
I have a two-column file that you can create as follows
cat > twocol << EOF
007 03
001 03
003 01
137 12
001 11
002 01
002 02
002 03
001 02
002 04
137 94
010 21
001 01
EOF
The resultant file, ...
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1
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How to combine ...if $x and a here-doc in perl? [closed]
How is one supposed to write this?
print <<EOF; if $x
bla
EOF
I think it is called postfix notation, and a here-doc. I get a syntax error.
OK, I guess I'll just use
print "bla" if $x;
...
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3
votes
7
answers
434
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How can I print the longest sequence of lines featuring numbers smaller than a threshold?
I am learning Perl, but I don't know how to solve this problem.
I have a .txt file of the following form:
1 16.3346384
2 11.43483
3 1.19819
4 1.1113829
5 1.0953443
6 1.9458343
7 1.345645
8 1....
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1
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How to use `perldoc` within Emacs (shell)?
While programming using Emacs, you frequently consult manual pages.
My environment is text-based Emacs via SSH.
While I can open "Normal" manual pages in Emacs using the man command ((man ...
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Search and replace content
PIN A
1 1:3 0:8
0 0:0
PIN B
1 1:0
0 0:0
Z Z:0
PIN C
1 1:3 0:8
0 0:0
Z Z:0
I would like to change the content on PIN A & PIN C only without affecting PIN B to
0 0:3
Z 0:3
Can't seem to find a ...
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1
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Report sed changes + corresponding perl syntax
Newbie learning Linux and perl:
I would like to (a) search-replace strings, (b) match filename pattern .myfile., (c) look recursively in subdirectories, and (d) print the line number, file name, ...
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1
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7
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Find all lines between two patterns, EXCLUSIVE of the second pattern?
Consider that I have the file listed below. I need to select all lines from every instance of the regex pattern Word A to before the regex pattern Word D.
Word A
Word B
Word C
Word D
Word E
Word F
...
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0
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1
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getting started with PDL for cluster analysis PDL::Stats::Kmeans
I guess first up is the Question " is perl data language dead ?" I'm not finding any active discussions or user q&a
sorry for not tagging this better I dont have the rep'
my problem area ...
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Perl's `kill` is using `$! == Errno::EINTR` unexpectedly
I wrote a network daemon that forks off children to handle TCP connections.
On SIGINT the main process triggers a kill for each child in order to clean up and to collect some final statistics.
In ...
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2
votes
3
answers
821
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ARGV[] not accepting the argument
I have a shell script that I am trying to pass a date argument to ARGV[1] but the script is giving a blank output
Here is the command:
#!/bin/bash
dt=$(date -d "yesterday" '+%m%d%Y')
cat /...
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4
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4
answers
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Ist it possible to check the peer address before accepting a TCP connection?
I wrote a simple Perl server that listens on a TCP port/socket, accepting connections.
Now I wonder:
When wanting to implement address-based access control, is it possible to check the address of the ...
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3
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bash + how to verify folders under specific path are ended with number/s
I want to check the folder/s under /var/kafka that all them are ended with number otherwhile I will exit with error
ls -ltr /var/kafka
drwxr-xr-x 399 kafka kafka 28672 Nov 9 13:10 data6
drwxr-xr-x ...
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2
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59
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rename - move [ ] delimited part of filename to end of filename
I've been playing with the perl implementation of the rename tool in cygwin having finally got it working via installing from cpan.
It's been a long time since i played with this stuff so I'm a bit ...
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2
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4
answers
211
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Parse text file add semicolons before and after numbers; join all other words that are before/ between numbers with hyphens
I have a text file with accounts like:
Input Sample
Paid 100 15/02/2022 3000
recd 50 15/02/2022 nelur trip 3050
PAID 80 25/03/2022 Adjusted towards trip 3130
14 PAID 50 26/03/2022 Given to Nate Cash (...
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1
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470
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How to remove characters from end of a line till a particular character in perl
my string is like
$varin="wer.try.iuy.oiu.qert"
i wanted to remove characters starting from end of the string till "." is encountered.
expected output:
wer.try.iuy.oiu
have tried ...
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3
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Replace new lines at end for those lines whose 2nd field in colon separated file span over to multiple line
I have got multiple files with different set of contents but the pattern is same across mulitple lines in different files.
sample input file : cat -n test.txt
1 adjfkhjdhfkjd: ...
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1
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395
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int seems to be not int in a used perl library
A peculiar phenomenon is on my mind. As you may know, dealing with a mail server directly exposed to the internet can be quite the 'joy' with various individuals attempting to break into it or use it ...
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3
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Perl: change in interpretation of shell symbols in system() invocation?
Today I noticed that something changed in Perl, probably recently, in the way it runs shell commands. Could someone explain what has changed? I cannot find the answer myself and sadly we learned about ...
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2
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perl: replace a string with variable containing new lines (line breaks)
I want to make edits containing meta characters. Here https://stackoverflow.com/questions/29613304/is-it-possible-to-escape-regex-metacharacters-reliably-with-sed one of solutions is via perl with s\Q ...
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4
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awk add a column if it doesn't exist
I would like to add a column 3 (description) if it does not exist in a ';' delimited file. example;
#Gene;Transcripts;Description;Group
gene1;G1a,G1b,G1c;gene1 is a good gene;6
gene2;G2a,G2b,G2c;gene2 ...
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0
votes
1
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535
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Check if two IP addresses are in a range
Using bash or perl on a minimal installed Linux, I am trying to validate two IP addresses if there are in a range.
I came across a bash script that works well, but the fact that it prints all the IP ...
- 1,607
4
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3
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Renaming files in Linux using perl scripting
I have a set of files with prefix, say "pre_", on a Linux machine and I just want to rename all of these files by removing that. Here is the perl code I wrote it doesn't throw any errors, ...
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1
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View perl module install error AFTER installed
When installing Perl modules (prerequisites for another program), some module showed me an incompatibility warning and said something about needing to downgrade a package. I thought I would get back ...
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1
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Error installing perl BerkeleyDB module
I'm trying to install a program which has various perl dependencies. One of the perl dependencies (BerkeleyDB) fails during install. I know very little about perl. Is there a way for me (as a user) ...
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0
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1
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553
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Is PERL5LIB setting needed?
I am copying the following systemd service file from an old server to a new one. I'm new to perl, and trying to understand what else needs to move with the service file (aside from the /usr/local/...
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1
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Pipe null terminated file paths twice to same output, but second time sorted by basename
So, let's say I have a script that uses find to print paths with null-terminated filenames.
I also want to print another version of the output where each path is sorted by its basename. I want to ...
- 141
0
votes
4
answers
658
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Remove hostnames from URL with sed/awk
I got lists of urls with different domains and I want the hostname removed with sed, awk or something similar and only keep the path. There are no urls with port or username@password in it.
input:
...
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How to replace the contents of out.txt with in.txt in a third file?
I have three files, main.txt, out.txt and in.txt. I want to replace every occurrence of the contents of out.txt in main.txt with the contents of in.txt.
Both out.txt and in.txt may contain multiple ...
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3
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How to deal with CRLF, CR line endings
I have a Perl script that parses data sent to me from a bunch of school districts. I'm adding a new school and have run into a problem I've never faced before. When I do $line = <INPUT>, it ...
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0
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Processing large blocklists with GNU Parallel
This is an ongoing project that has undergone a major update to speed up list processing. Here is the homepage for anyone interested!
It processes lists defined in lists.json by transforming the list ...
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1
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How to find the text between the nth occurence of a character and occurence n+1 with perl-rename?
perl-rename 1.14-1
Arch Linux: linux 6.2.12.arch1-1
I have a directory/folder with several subdirectories, all are named by one of the following patterns
Status quo of existing patterns
something-...
- 914
2
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1
answer
396
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How can I pass variables from a Perl script to a Bash script?
I got the duty to make a fix to an ancient Perl script our company uses, I haven't even looked at Perl in about 20 years. So I want to pick up a couple of the variables, and dump them to the ...
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0
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429
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Update package perl-*
I have a linux machine Oracle Linux Server 8.7 with kernel 5.4.17-2136.317.5.3.el8uek.x86_64.
Using the yum check-update command, I noticed that there are a number of perl-packages that I can't update....
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1
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201
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Change file name based on contents
I'm trying to rename a set of files based on what is in the file itself. I have likely more than a thousand files to rename by the time I'm done. I have code that will get me the first part of the ...
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0
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41
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ubuntu server 22.04.2 LTS not writing to perl based txt files?
I just installed Ubuntu server to create a home webserver for personal use. I added Virtualmin and my pages and cgi all come up as expected.
The problem I noticed is when I attempt to open, write to ...
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2
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131
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what does syntax .= means in perl
I came across a Perl script which uses following .= syntax
$key .= $descriptions[$i];
what does .= means here
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5
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118
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Remove three lines from file until a match
982
01:25:09,473 --> 01:25:10,978
Stay with me.
983
01:25:09,473 --> 01:25:10,978
Stay with me.
984
01:25:15,390 --> 01:25:18,484
( MAJESTIC MUSIC )
I want to delete three lines below 984 (...
2
votes
2
answers
251
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Perl script to remove repeating header/trailer in file
I have created a perl script to merge 10 file in one. Each file has Keyword header/Trailer in file. So merged file has multiple header and trailer keyword. but I require the header and trailer to be ...
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3
votes
3
answers
207
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Print a line matching pattern1 unless next line contains pattern2
I want to match lines that have foo unless the next line contains bar. So given a file containing:
1 foo 1
foo 2
baz bar bap
only 1 foo 1 would print. I got this to work using a negative lookahead /...
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0
votes
2
answers
274
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perl has problem if filenames contain dashes
... | perl -pe "s/([^$filespec]*)($filespec)/ ...
So I have a function where the above construction works fine if $filespec is most things. However if there's a dash in the file name I get an ...
- 2,527
3
votes
1
answer
274
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Different encoding/Unicode interpretation using terminal vs using shell script
I was working on a keymap script (map keys from one language keyboard layout to another). And after a lot of hard time trying to get everything working I found out that different characters are ...
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