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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.

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FTP files from one remote server to another

I am trying to find out how I can transfer files from one directory/server to another directory/server? What I need to consider is that I should transfer files that are created TODAY only. i.e. the ...
3
votes
1answer
274 views

Is it a good idea to supplement shell script with perl purely for use of regex?

I'm looking for a simple way to utilize regex in a UNIX shell script where not every system will have perl extensions built into grep. What is really helpful about perl regex here is back/forward ...
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1answer
1k views

install RPM packages using perl

I'm trying to install RPM package using 'yum' through perl. But, the package is prompting to enter 'Y/N' during the install. How can i do a silent install?
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2answers
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How to know reason of a process going to sleep state and wake it up?

When I do 'top' , I see my perl script process in 'S' state. Is there a way to know, what is making this perl process go in sleep state and ways to wake it up? Any way to debug to give more insights ...
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2answers
525 views

Linux - get shared memory values from Perl script

I'm trying to get shared memory information from a linux box. I'm looking for shmmax, shmmni, shmall, msgmax, msgmni, semmsl, semmns etc. How to get all those values from a Perl script. any help is ...
9
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4answers
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Find files with same name but different content?

I want to generate a list of files that have: Same name Different content in a directory (including all children directories and content). How to do? Bash, perl, anything is fine. So, two files ...
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votes
3answers
1k views

How to move files into newly created directory on condition in shell/perl

It was a mess of music files and directory. It is needed to perform the below operation over multiple directories at once: If the directory contains ".jpg" files, then create a new directory "...
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10answers
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How to insert the content of a file into another file before a pattern (marker)?

File1 contents: line1-file1 "1" line2-file1 "2" line3-file1 "3" line4-file1 "4" File2 contents: line1-file2 "25" line2-file2 "24" Pointer-file2 "23" line4-...
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1answer
226 views

How to get the filename if particular regexp is present in the file in Perl

In a directory containing many files, if a particular regexp (or format) was found in file, I'd like to get that filename Example: If the word "rama" is found in file called ramayana, print the ...
6
votes
1answer
4k views

Escaping of meta characters in basic/extended posix regex strings in grep

Is it possible to escape all meta characters of a string inside a variable before passing it to grep? I know similar question has been asked before on SE (here) and also a good explanation here, but I ...
3
votes
1answer
7k views

Apache cannot fork: cannot allocate memory

I am running apache on Fedora with mod_perl. The server forks a process to send an email frequently - and the fork exits. Suddenly, I got: Cannot fork: Cannot allocate memory. There was plenty of ...
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3answers
2k views

Parsing XML from a shell script

I have a datafile like this: <Key name="com.ahsay.afc.cpf.UserGroup" content="" allowMultiple="Y"> <Value name="rsv-id" inheritParentAttribute="Y" type="string" data="1328200856753" /&...
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3answers
875 views

Prevent init daemon echoing on TTY

Below is an init script which starts/stops a daemon. The daemon is unfortunately printing the parsed packet data (from /home/nuthan/program/server), a socket server written in perl, listening to a ...
0
votes
1answer
2k views

Manually assign a value when inet_ntoa does return an ip address

Code: foreach $hostname (@hostnameUniqueSorted){ $ipaddr = inet_ntoa((gethostbyname($hostname))[4]); if(chomp($ipaddr) =~ '^$') $ipaddr == "ip not avail"; <-- doesn't work } If the host ...
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4answers
4k views

Extract IP address from a string

The Linux host command returns: hostA.domain.com has address xx.xxx.xxx.xx How do I get just the IP address and put it in the $ipaddr variable? open(FILE, "hostlist.txt") or die("Unable to open ...
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votes
2answers
2k views

how to apply this patch

There is a patch fix for perl module net::ssh2 it fixes a seg fault error that happens on some machines. It's located here: https://rt.cpan.org/Public/Bug/Display.html?id=36614 I downloaded the ...
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6answers
3k views

Delete lines beginning with #

How do I delete lines beginning with a #, given that there can be whitespace on the left and right of the #? # Master socket provides access to userdb information. It's typically
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votes
3answers
11k views

Regex & Sed/Perl: Match word that ISN'T preceded by another word

I'd like to use sed or perl to replace all occurrences of a word that doesn't have a certain word in front of it. For example, I have a text file that contains a plot of a movie and I want to replace ...
2
votes
1answer
754 views

How to insert a first column to many files + how to convert unix time to normal time

There are many-many files in a directory that has e.x.: the following content: INPUT: root 1324711901 sshd 1272725792 And I'm searching for a solution how to convert the content of the ...
0
votes
2answers
1k views

Need to install MySQL Client libaries but RPM not installing them

I'm trying install the MySQL Client libraries for the Perl Mod of the same name but when I run sudo rpm --install -v --allfiles MySQL-client-5.5.16-1.linux2.6.i386.rpm and querying the rpm database ...
2
votes
2answers
494 views

perl regex replacing globally when global not selected

I'm using Ubuntu 11.04 and wrote a small script that searches within text files for certain "tokens" and replaces with some a prewritten snippet from a template file of the same name. The text files ...
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votes
3answers
284 views

What does . match?

In working with regular expressions, I have been told that a dot character . will match everything. Except for newlines \n. Are there any other exceptions? What about the NUL character \0, or the ...
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votes
2answers
4k views

How do you determine if AIX 5.3 has perl installed?

Simply put, how do you determine if AIX 5.3 has perl installed as non-root?
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votes
1answer
2k views

Renaming files to have lower case extensions with 'rename'

I'm trying to currently rename a large set of files and have been using quite kludgy methods to do so, such as: rename 's:(.*)\.MOV:$1.mov:g' *.MOV rename 's:(.*)\.JPG:$1.jpg:g' *.JPG What I'd ...
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votes
5answers
2k views

How can I remove a specific line from a file only if there are other lines in the file?

How can I remove a specific line from a file ONLY if there are other lines in the file? For example, don't touch this file: cat file.txt ASDF but remove "ASDF" from this file: cat file.txt ASDF ...
5
votes
4answers
8k views

How to filter IPv4 and IPv6 addresses?

echo "1.1.1.1" | awk '/[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*/ {print $1}' How can I filter IPv4 addresses in a script, and how can I filter IPv6 addresses. I mean more precisely then this so the oneliner ...
3
votes
1answer
3k views

How race conditions affect reads and writes (that happen at the same time)

Let's say I open a file a for reading. What if an application, let's call it aWriter writes to this file in random intervals. Are there any possibilities of me receiving improper file contents if I ...
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vote
1answer
763 views

How can I get mod_perl running in Arch Linux?

I've installed mod_perl, and even tried enabling it, unfortunately it seems to be preventing apache from starting. LoadModule perl_module modules/mod_perl.so here's the error. /usr/sbin/apachectl: ...
2
votes
4answers
6k views

ncurses based menus

How can I build an ncurses based menu? Are there any other solutions for building "menus" for use on the console? I just need an "inter-operating system" (all non-windows :P) solution. Are there any ...
7
votes
1answer
517 views

Passing clicked links in rxvt to a script

I start my browser vimprobable in tabbed like so: "`tabbed -d > /tmp/tabbed.xid`; vimprobable2 -e `cat /tmp/tabbed.xid`" [1] I am then able to send all new instances of vimprobable to tabbed (and ...
2
votes
1answer
1k views

How do I make a droplet/.app in platypus for my unix command?

This is my sample code from the platypus tutorial. I am trying to make it work with a command named pymol, and I want it to open .pdb files or open just pymol. I know nothing about perl, but I have ...
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vote
1answer
906 views

Need command-line program to download all of http:// https:// scp:// ftp:// style links (on e.g. ubuntu)

I'm writing a perl program where I want to accept all kinds of "file names" from the user, including /home/foo/bar.txt and scp://server/some/file.txt or whatever. And then I thought that if I can find ...
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vote
1answer
1k views

Find server with small ping latency (my script, but can anyone write it in e.g.: Perl?) [closed]

I want to download OpenBSD with FTP with a script, and I want to download it from a server that is near me. So I want to choose a mirror that has low "ping latency". I wrote a little script, that ...
34
votes
9answers
22k views

How can you combine all lines that end with a backslash character?

Using a common command line tool like sed or awk, is it possible to join all lines that end with a given character, like a backslash? For example, given the file: foo bar \ bash \ baz dude \ happy ...
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vote
1answer
1k views

How to convert <a href=“http://xy.com”>XY</a> to [http://xy.com XY]?

Just for editing Wiki's.. So i have this input [from a larget text]: TEXT TEXT BLA-BLA RANDOMSTRINGS BLA-BLA TEXT TEXT BLA-BLA RANDOMSTRINGS BLA-BLA TEXT TEXT <a href="http://xy.com">XY</a&...
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votes
5answers
6k views

Replacing text from a list of replacements. Added complication: backslashes

I have a file A that contains pairs of strings, one per line: \old1 \new1 \old2 \new2 ..... I would like to iterate over file A, and for each line perform the replacement (e.g. "\old1 -> \new1") ...
10
votes
6answers
4k views

Is there any alternative to grep's -A -B -C switches (to print few lines before and after )?

grep -A 2 -B 3 prints 2 lines after the grep string and prints 3 lines before. grep -C 3 prints 3 Lines before and 3 lines after Unfortunately, the grep I'm using does not support these options. ...
2
votes
3answers
1k views

Get last set of non-empty lines

I'm running a cron job which should get only the last result of iostat -d 1 2. This requires some parsing: What is the simplest way to get the last set of non-empty lines from standard input to ...
11
votes
3answers
874 views

Is there a way to make perl -i not clobber symlinks?

A friend of mine points out that if you do: perl -pi.bak -e 's/foo/bar/' somefile when "somefile" is actually a symlink, perl does just what the docs say it will do: It does this by renaming the ...
2
votes
2answers
274 views

Perl find and replace is writing every file

Here's the test script I'm running matt@server:~ $ cat test.sh #!/bin/bash mkdir test cd test echo "has the string foo" > yes.txt echo "hasn't the string" > no.txt ls -l --time-style=full-iso ...
5
votes
3answers
7k views

piped program in sendmail's /etc/aliases

I'm trying some sort of auto-subscription via a homegrown script. I know it can be achieved by mailing lists such as Mailman but I also want to learn at the same time on how to do it by hand. Here's ...
4
votes
1answer
2k views

Query DHCP server leases from Perl script

I have a Windows 2003 server and need to poll the DHCP lease information from it with a perl script that is running on a Ubuntu server. Then I need to analyze & store the information in a mysql ...
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votes
3answers
23k views

How can I install perldoc on Ubuntu?

Ubuntu 10.10 comes with Perl 5.10.1 pre-installed, but strangely enough perldoc isn't part of the package. $ perldoc You need to install the perl-doc package to use this program. How can I make this ...
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vote
4answers
3k views

Using regex to see if a UNIX process is up

In UNIX, I am checking to see if a process is up by executing the following command; E.g. psg dtllst pe99 This returns the following output if the process is running; UID PID PPID C ...
11
votes
1answer
16k views

Execute Nohup command with input

In UNIX, I have a process that I want to run using nohup. However, this process will at some point wait at a prompt where I have to enter yes or no for it to continue. So far, in UNIX I have been ...
9
votes
1answer
8k views

Replacing multiple lines in sed or awk [closed]

I'm trying to use sed or awk to replace 5 lines in a smb file but I just don't have any idea how to deal with the newlines.