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Category Archives: Programming Languages
Perl – Using Pattern-sequence Memory with Regular Expressions
Pattern-sequence memory is very useful when you want to match the same character in several places but don’t care which character you match as long as all occurrences are the same character. For example, the below code matches the date … Continue reading
Posted in Perl, Programming Languages, Technology
Tagged pattern memory, pattern-sequence, pattern-sequence memory, Pattern-sequence Memory with Regular Expressions, perl, perl regular expressions, regex, regular expressions, sequence memory, Using Pattern-sequence Memory with Regular Expressions
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Perl – Obtain the File Size
Here is a cool one line Perl script you can use to quickly obtain the file size of a file. The syntax to run the script is “perl [scriptname] [filename]”; in the below example I use the script itself as … Continue reading
Posted in Perl, Programming Languages, Technology
Tagged -s, file size, file size operator, get file size, perl, perl file size operator, perl get file size
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Perl – Writing the Linux ‘cat’ Utility
The below Perl code will give you similar results compared to the Linux ‘cat’ utility. At the command prompt, just enter “perl [scriptname] [filename1] [filename2] etc …
Perl – File-Test Operators
In Perl, file-test operators are useful for determining the status of a file. Some of the operators below refer to the “real user” which is the User ID specified at login rather than “effectve User ID” which refers to the … Continue reading
Perl – Converting the Time from 24 hr to 12 hr Format
Below is a Perl script that demonstrates how to appropriately convert the current time from 24 hr format to 12 hr format. The ‘convertToTwelveHr’ subroutine does all the work here. The 24 hr input value is passed into the subroutine … Continue reading
Posted in Perl, Programming Languages, Technology
Tagged 24 hour to 12 hour, 24 hr to 12 hr, Converting the time from 24 hr to 12 hr format, localtime, localtime function, localtime subroutine, perl, Perl 24 hour to 12 hour, Perl script, Perl script that converts time from 24 hr to 12 hr
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Perl – merging files
Below I demonstrate a quick method of merging two files into a third file using Perl. The program merges two files together into a third file by writing one line from file one to file three and then writing one … Continue reading
Posted in Perl, Programming Languages
Tagged combine files, file merge, merge two files, merging files, perl, perl code
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Perl – Initial Values and Context Based Evaluation
It’s important to remember that in Perl all scalar variables have an initial value of the null string, “”. You do not need to define a value for scalar variables unless you are using “strict” mode. Knowing this, what do … Continue reading
Screen Scraping with Perl to get the top 25 Websites and the Web Servers they use
This was a really fun little script I wrote that I thought I would share with everyone. I basically wrote a Perl script using the popular LWP Perl module to screen scrape and obtain the top 25 sites and the … Continue reading
Posted in Data Mining, Hacks, Perl, Programming Languages, Technology
Tagged alexa, alexa.com, bot, bots, download webpage, hack, hacking, HTTP, HTTP header, HTTP request, HTTP response, Library for WWW in Perl, libwww-perl, LWP, LWP::Simple, LWP::UserAgent, perl, screen scraping, script, scripts, server, Simple, top 25 websites, UserAgent, web server. web servers. automate
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Perl – Get files and directories with the glob function
Recently, as part of a larger Perl application, I had to get all the files and sub-directories of the working directory. Using the built-in ‘glob’ function, I was able to quickly implement a subroutine to do this and also differentiate … Continue reading
Posted in Perl, Programming Languages
Tagged get directories, get files, get sub-directories, glob, glob function, perl, perl glob, perl glob function
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