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.
1,339
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3
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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 ...
- 1,401
0
votes
2
answers
61
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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 ...
- 1,083
5
votes
4
answers
445
views
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 ...
- 139
0
votes
1
answer
66
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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 ...
- 1,524
4
votes
3
answers
810
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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, ...
- 51
0
votes
1
answer
15
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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 ...
- 1,630
1
vote
1
answer
36
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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) ...
- 1,630
0
votes
1
answer
41
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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/...
- 1,630
0
votes
0
answers
17
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Issues when trying to find a file on EFS from an EC2 instance running Perl 5
We have Perl 5 installed on EC2 instance running RHEL 8. When we try and run perl script to located a file on EFS, it takes around a minute to locate the file after it was created on the EFS. There ...
0
votes
1
answer
26
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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 ...
- 139
0
votes
4
answers
198
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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:
...
- 175
-1
votes
3
answers
124
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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 ...
- 17
1
vote
3
answers
719
views
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 ...
- 59
2
votes
0
answers
84
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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 ...
- 131
0
votes
1
answer
50
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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-...
- 844
2
votes
1
answer
170
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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 ...
- 21
0
votes
0
answers
133
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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....
- 31
0
votes
1
answer
83
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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 ...
- 1
0
votes
0
answers
27
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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 ...
- 1
0
votes
2
answers
108
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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
- 37
0
votes
5
answers
105
views
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
177
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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 ...
- 37
0
votes
0
answers
41
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trouble installing DBD::CSV module on redhat 8
I'm trying to install the cpan module DBD::CSV onto a redhat 8 workstation. In the cpan shell I type:
install "DBD::CSV"
this runs for a while and finishes like this:
...
Appending ...
3
votes
3
answers
186
views
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 /...
- 43
0
votes
2
answers
171
views
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 ...
- 2,145
3
votes
1
answer
187
views
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 ...
- 111
6
votes
1
answer
2k
views
What are the different versions of the rename command? How do I use the Perl version?
This is a mess. How do I know which command to use when we expect Perl's rename with s/// sed-like syntax, when there're tons of different implementations of rename, that are different versions of the ...
- 32.3k
0
votes
3
answers
343
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How to convert seconds to hh:mm:ss.ms when getting difference between 2 times
I performed a calculation that converts current timestamp giving milliseconds as well using perl command such as below:
perl -MTime::HiRes=time -MPOSIX=strftime -e '
$now = int(time() * 1000);
printf &...
0
votes
2
answers
253
views
Remove multiple occurrences using SED command
We had a requirement to remove all /t characters that are not followed by quotes
sed 's/\\t\([^"]\)/foo\1/g'
this command worked good for single occurrence. What option do we need to add remove ...
- 1
0
votes
1
answer
68
views
Missing EXTERN.h file when installing claws-mail on Fedora 37
I've trying to compile Claws-mail but got error:
perl_plugin.c:54:10: fatal error: EXTERN.h: No such file or directory
54 | #include <EXTERN.h>
I've installed perl-core perl-devel was ...
- 9,662
1
vote
2
answers
1k
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How may I replace a string in an XML file?
I am trying to replace the string inside an XML file.
From
<hello="value" exampleno="xxxx:yyyyyyyy/dd=eeeee-ffffff,aa=bb ccc,dd=eeee,ff=gggg,hh=iii,jj=kkk,ll=mmmm" />
I want ...
- 19
1
vote
1
answer
56
views
How many codes written by perl in debian?
My debian os:
cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"
NAME="Debian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
...
- 99
1
vote
6
answers
508
views
Find and replace a multi line text file in another multi line text file
I fought with it for so long but I am now completely out of ideas. Maybe someone here will be able to help me. Here is what I want to achieve:
file_1.txt:
# Some comment
some_variable="test"
...
- 121
3
votes
1
answer
248
views
Using perl's rename to renumber a list of files, starting at a certain value
I'm trying to renumber a list of files, which at a given point in their filename have one index consisting of a four-digit number. These files are consistently output starting from 0001, but need to ...
- 33
0
votes
1
answer
415
views
Writing to unix socket file as fast as possible
I'm trying to write with perl to a unix socket file as fast as possible but failing on full message buffer. I tried autoflush and manual flush without success.
use IO::Select;
use IO::Socket::UNIX;
...
- 11
0
votes
1
answer
155
views
How can I create a .txt file containing data being generated in real-time in Linux terminal when a program is running?
I am running an AutoDock Vina program (using a Perl script) in Linux.
It generates lots of important data
(regarding binding free energy of protein-ligand docked complexes).
However, I cannot save ...
1
vote
1
answer
112
views
How can I condense several regex to a one-liner?
I'm having trouble condensing several regex down to an efficient one-liner. I have file names which are named like this: Something (0482) - a123b456 - Something [00xcf bxc v32 Something]. I'd like the ...
- 1,835
0
votes
1
answer
81
views
clusterssh: prevent windows being arranged alphabetically
I am using cssh on Debian 10 (package clusterssh 4.13.2-2).
when I connect to multiple servers:
cssh foo bar zz aa
cssh will open 4 terminals and ORDERS THEM ALPHABETICALLY !!!
So that I get the ...
1
vote
3
answers
116
views
Detect leaf directories in Perl
For a Perl script I'm working on, I'm looking for a fast and reliable way to find all subdirectories (transitively) of a given directory which are leaves, i.e. those not having any subdirectories of ...
- 518
5
votes
5
answers
740
views
How can I replace multiple substrings from multiple lines in a file matching a pattern from a different file?
I have a file that contains multiple IP addresses and hostnames, and another file that contains some folders with many IP addresses per line.
ip_hostname.txt
host1 10.1.1.1
host2 10.2.2.2
host3 10.3.3....
- 51
1
vote
1
answer
41
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"Total In-/Out- coming connection awareness" - script?
once I had found a bash (or Perl maybe; it's so long ago, that I wasn't knowledgeable about bash enough to tell one set of hieroglyphs from another set so to speak) script that filtered the open files ...
- 405
1
vote
3
answers
317
views
Filter git log of pom.xml using regex with grep/perl
I'd like to filter the content of a log of a pom.xml file using a regex.
I created it on regexr and it works using PCRE; this is my regex:
commit \K[a-z0-9]*(?=[\s\S]*\+.*<version>1.2.0)
I then ...
- 113
0
votes
0
answers
441
views
base64 decode as save as multiple files
I have a file(har file saved from web developer" that contains the base64 encoded value of multiple video*.ts files. I am interested to decode the base64 part and save as multiple ts files if the ...
- 101
2
votes
1
answer
440
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How do you modify the RPM spec file to require perl libraries on centos 7?
I normally start with a Minimal Centos 7 and run
yum install perl-libs.x86_64
This works perfectly.
I am now trying to create an RPM spec file that uses the "Requires" clause to package ...
- 193
1
vote
1
answer
139
views
Why does Debian package Scalar::Util in libperl and perl-base?
I was just checking something out on Debian, when I use apt-file to search for Scalar/Util.pm a CORE Perl module I see three results,
$ apt-file search Scalar/Util.pm
libperl5.34: /usr/lib/x86_64-...
- 29k
1
vote
0
answers
302
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how to validate Perl Modules Installed in Ubuntu
I have a list of Perl Modules which needs to be installed on a new server . List of Perl Modules is like this
perl-Expect
perl-JSON
perl-Net-OpenSSH
perl-Test-Most
perl-DBD-Mock
Earlier we were ...
- 237
0
votes
1
answer
487
views
Perl @INC Path Help
I got handed over a Perl script which fails to run because the path to the Perl is deleted.
How can I modify the path such that I can point it to /opt/perl/lib/5.28.2
Any help will really be ...
- 313
3
votes
2
answers
207
views
Find regex occurrances on block device (line length buffer issue)
I'm trying to find all numbers on two block devices that start with a # character, are between 1635700000 and 1653699999, and end either with a null character (\0) or a linux newline (\0xA).
I came up ...
- 1,178
1
vote
2
answers
163
views
Remove all characters from string, except specific multibyte range
How would one use sed or another tool to remove all characters except a specific multibyte range?
For instance, the range \xd8\xa0 - \xd9\x8a covers Arabic characters encoded in UTF-8. This was my ...
- 15.6k
0
votes
8
answers
1k
views
Rewriting log parsing script in Perl or Python (get rid of awk)
I need accomplish a task of filtering activity of bots in the log file.
Solution should only show records meeting following criteria
user logged in, user changed password, user logged off within ...
- 141