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 ...

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votes
1answer
950 views

/bin/sh: ./check-dependencies.pl: not found — but check-dependencies.pl exists!

I'm trying to build Moses, but when I run make I get the following output: minakshi@minakshi-Vostro-3500:~/Desktop/working-dir/moses/scripts$ make release # Compile the parts make all make[1]: ...
4
votes
1answer
874 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
votes
3answers
3k 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 ...
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vote
6answers
2k views

Repeat each line multiple times

Would like to have each line in a file repeated a fixed number of times. e.g. have each line repeated four times: a b c becomes: a a a a b b b b c c c c I've done some searching, and there are ...
16
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2answers
7k views

What does ${1+“$@”} mean in a shell script, and how does it differ from “$@”?

In the Perl documentation, perlrun(1) suggests launching Perl scripts using a bilingual shell/Perl header: #!/bin/sh #! -*-perl-*- eval 'exec perl -x -wS $0 ${1+"$@"}' if 0; What does ${1+"$@"} ...
7
votes
6answers
2k 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 ...
6
votes
1answer
821 views

How can I replace a string in a file(s)?

Replacing strings in files based on certain search criteria is a very common task. How can I replace string foo with bar in all files in the current directory? do the same recursively for sub ...
10
votes
4answers
1k views

Why is Perl installed by default with most Linux distributions?

Just curious. The title says it all: Why is Perl installed by default with most Linux distributions?
7
votes
1answer
332 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 ...
6
votes
3answers
509 views

Is there a perl or awk solution for this problem?

I have an input file (input.txt) like below. id1 id2 name weight 53723848 12651711 timburnes 1.36667 53530214 12651711 timburnes 1.51191 53723848 53530214 timburnes 1.94 764157 ...
5
votes
1answer
177 views

Execute a command within 'sed'

I have a list of random memory addresses saved in a text file, and I need to sed them out, decode them, and save them back to my file. However, the decoding operation I'm trying to perform is handled ...
4
votes
1answer
63 views

Regex this question format into LaTeX

1. Lorem ipsun la la la? 1. Sopor 2. Stupor 3. Torpor 2. A patient has Lorem? 1. Sopor 2. Stupor 3. Somnolentia 4. La 5. Coma 3. Doesn't Response to strong external irritants is short. Tendon, ...
4
votes
6answers
98 views

Only show the lines that are in all textfiles at least once

a.txt cat a.txt a b x c b.txt cat b.txt d e a f the q: SOMEMAGICK *.txt a Q: how can I show only the lines that are in all *.txt files?
3
votes
7answers
498 views

Finding the maximum of the values in a file

I have a file which contains several numbers, as follows. 21 12 33 35 21 12 33 44 52 63 14 12 23 34 11 12 13 53 1 12 43 33 44 How can I find the maximum of these values, which is 63? I wanted to ...
1
vote
1answer
86 views

How do I modify this Perl solution so that it will substitute embedded double quotes with single quotes?

Previously in this question: "string having doublequotes in between apart from the enclosing quotes" @BernieReiter asked a follow-up question where he wanted to take CSV entries such as the following: ...
3
votes
4answers
241 views

merge 2 rows based on the same column values

I have a file like below. 47196436 47723284 name1 1.77273 42672249 52856963 name2 1.06061 52856963 430695 name2 1.16667 55094959 380983 name3 1.55613 17926380 55584836 name4 1.02461 3213456 34211 ...
3
votes
2answers
185 views

case sensitive substitution; same target ids

I am struggled myself to make a case sensitive replacement in a text file. Please find below a segment of my sed file that I am running as sed -f file.sed < input.txt > output.txt ...
3
votes
1answer
292 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 ...
3
votes
4answers
1k 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") ...
2
votes
5answers
2k views

Perl script, do cd on terminal

In Script to change current directory (cd, pwd) it is shown how to run a bash script that changes terminal directory. But how do i run a perl script that runs a bash script that changes terminal ...
2
votes
1answer
165 views

perl-get input, check conditions

cat input1.txt ##gff-version 2 ##source-version geneious 5.6.4 Xm_ABL1 Geneious CDS 1 168 . + . Name=Xm_ABL1;created by=User;modified ...
0
votes
1answer
106 views

Error trying to call find from perl

use warnings; use File::Find; my $srceDir = "//mnt/Share_Drive/Verizon PM&T/Capture Files/"; opendir(DIR, $srceDir) or die "Can't open $srceDir: $!"; my @files = (find -type f -newermt "12 Feb ...
-1
votes
1answer
114 views

Is Perl obsolete? [closed]

Is it worth learning Perl or it is an obsolete language and other languages should be learned instead of it? I am a newbie and I would appreciate it if someone could shed light on this subject and ...