Browsing AuthorCelso

September 7, 2004

Determine Disk Usage

This command will show the number of KBs used for all non-hidden files and folders in the current directory:

du -sk * | sort -rn

August 11, 2004

Find By Contents

This will recursively search all the files, with a certain filename pattern (in this case *.h) in a certain directory, that contains a certain text pattern in its contents (in this case ‘DeviceDriver’).

find . -name '*.h' -print0 
| xargs -0 grep -n -e DeviceDriver

August 2, 2004

CGI To Display Module Documentation

Here’s a CGI to display a module’s POD. The module has to be in the $INC. This is great for providing documentation to internal modules.


# save this as showdoc.cgi
#!/usr/local/bin/perl
use strict;

use Pod::Html;
use CGI;
use CGI::Carp qw(fatalsToBrowser);

# Send out the header
print "Content-type: text/html", "nn";

my $q = new CGI;

my $module = $q->param('module');
require $module;

$| = 1;

chdir ("/tmp");

my $fullpath = $INC{$module}
    or die "$module not found";

pod2html("--infile=$fullpath", "--flush");

# Clean up the junk left by pod2html
END {
        unlink("pod2html-dircache");
        unlink("pod2html-itemcache");
}

To use this, say you want to view POD for Data::Dumper:


http://localhost/cgi-bin/showdoc.cgi?module=Data/Dumper.pm

July 24, 2004

crontab Format

[I could never remember this so I’m putting it here.]
These are the fields of a crontab file:


a b c d e /full/path/to/script

where

a = minute (0-59),
b = hour (0-23),
c = day of the month (1-31),
d = month of the year (1-12),
e = day of the week (0-6 with 0=Sunday).

* = every min, hour, day, etc.
*/10 = every 10 min, hour, day, etc.

July 21, 2004

Read A Text File

This will open a text file and read it line by line. As it is, it will just print each line to the screen, so very much like the unix ‘cat’ command, but could very well do anything on the line just read by replacing the cout statement.


#include <fstream>
#include <iostream>
#include <string>

void main() {
    string s;
    ifstream infile;

    infile.open("aaa.txt");

    while(infile >> s) {
        cout << s << endl;
    }
}