WiredRevolution.com » remove

Remove the envelope icon from the Gnome indicator applet

Ryan — Tue, 07 Dec 2010 19:09:31 +0000

In Ubuntu it can be difficult to customize the indicator applet which by default contains the sound, battery, Bluetooth, and empathy icons.

If you don’t use empathy and want to remove the icon there is no simple option to change. Since this is a default indicator icon you must completely remove the indicator-messages package to make it disappear.

$ sudo apt-get purge indicator-messages

Once you have removed the package you can log out and back into your account to see the changes take effect. Alternatively you can remove the indicator-applet and then add it back to the Gnome panel.

Convert text files within a directory from Windows to Unix format

Ryan — Wed, 07 Jan 2009 14:14:33 +0000

When a file is saved in Windows and then moved to a Linux system the formatting differences can cause a variety of problems. To effectively use these files you will need to change the format from Windows/DOS to Unix. This conversion occurs by simply removing the Windows carriage return characters.

I have explained how to use the tr command remove these windows carriage returns, but when you have a large amount of files to convert this can become tedious. As a solution to this I have written a BASH script to convert all text files within a directory.

#!/bin/bash

for file in /directory/to/convert/*
do
  if [[ -f $file && `file $file | grep text` ]]
  then
    tr -d '\r' < $file > "$file"_clear
    mv "$file"_clear $file
  fi
done

Remove Windows carriage returns with tr

Ryan — Sun, 30 Nov 2008 15:46:17 +0000

The end of a line in a UNIX text file is designated with the newline character. In Windows, a line ends with both newline and carriage return ASCII characters. If a file is saved in Windows and then moved to a Linux system these carriage returns can cause all sorts of problems. If the text file is a BASH script for example it will not run correctly since it doesn’t know how to interpret these characters.

You can verify that a text file has these Windows carriage returns by running the cat command with the ‘-v‘ option which shows the non-printing characters.

$ cat -v inputfile | head

first line^M
second line^M

You can see the carriage return characters, “^M” (Cntl-M).

CRLF = Carriage Return Line Feed

There are various was to remove these carriage returns. You can use the dos2unix command but this is rarely installed by default on a a Linux system. The easiest way then is to use the “tr” command utility which always comes standard.

The command uses the tr command which translates and removes characters. This will remove the carriage return characters.

$ tr -d '\r' < inputfile > outputfile

You can verify they are really gone by running the same cat command again.

$ cat -v outputfile | head

first line
second line

You can also run the file command.

$ file inputfile

inputfile:             ASCII text

Optionally you can now overwrite the original file.

$ mv outputfile inputfile

RPM Cheat Sheet

Ryan — Thu, 23 Oct 2008 05:07:10 +0000

RPM stands for Red Hat Package Manager. There are a variety of distributions besides Red Hat that use RPM to manage packages including Fedora, Mandriva, SUSE, CentOS, and Yellow Dog Linux among others. RPM uses a database to keep track of what packages have been installed on the system and where they are located. This functionality allows you to easily query, install, upgrade, and remove packages from your system.

RPM packages are distributed in the following format “...rpm”

Check the package information.
$ rpm -qi mypackage.1.2.3.x86_64.rpm

List the files that will be installed.
$ rpm -ql mypackage.1.2.3.x86_64.rpm

Install an RPM package with the ‘-i‘ option.
$ rpm -i mypackage.1.2.3.x86_64.rpm

Upgrade a package that is already installed.
$ rpm -U mypackage.2.0.0.x86_64.rpm

Remove a package. You only need to provide the package name and not the version or rpm suffix.
$ rpm -e mypackage

View all the installed packages on your system.
$ rpm -qa

If you want to see more output you can increase the verbosity by adding the ‘-v‘ option to any of these commands. To raise it even further you can add ‘-vv‘.