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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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 ...
5
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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 ...
4
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 ...
1
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1answer
766 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
523 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
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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 ...
1
vote
1answer
922 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 ...
1
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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
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9answers
23k 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 ...
1
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&...
4
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 ...
12
votes
3answers
897 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
275 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 ...
17
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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 ...
1
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.