Introduction to if 7.1.1. General At times you need to specify different courses of action to be taken in a shell script, depending on the success or failure of a command. Guide d'installation et de configuration de Linux Christian Casteyde Copyright © 2004 Christian Casteyde Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". Permission vous est donnée de copier, distribuer et modifier ce document selon les termes de la licence GNU pour les documentations libres, version 1.1 ou toute autre version ultérieure publiée par la Free Software Foundation.
Lesson 8: Expansion Each time you type a command line and press the enter key, bash performs several processes upon the text before it carries out your command. We have seen a couple of cases of how a simple character sequence, for example “*”, can have a lot of meaning to the shell. The process that makes this happen is called expansion. With expansion, you type something and it is expanded into something else before the shell acts upon it. To demonstrate what we mean by this, let's take a look at the echo command. echo is a shell builtin that performs a very simple task. It prints out its text arguments on standard output:
List of Bash online-tutorials Here's a list of some Bash tutorials. The primary purpose of that list is to lead beginners to good tutorials and not to the wrong ones. However, the secondary purpose is to provide information to increase quality of the linked tutorials. Parameter expansion One core functionality of Bash is to manage parameters. A parameter is an entity that stores values and is referenced by a name, a number or a special symbol. parameters referenced by a name are called variables (this also applies to arrays) parameters referenced by a number are called positional parameters and reflect the arguments given to a shell parameters referenced by a special symbol are auto-set parameters that have different special meanings and uses Parameter expansion is the procedure to get the value from the referenced entity, like expanding a variable to print its value.
Vim Cheat Sheat for Programmers by Michael Pohoreski Update: Version 2.0 is up! There are now 4 versions to chose from: (If you are wondering what the differences are between the screen and print: the screen has less color variations, and no gradients to make it easier to read.) One designed for on-screen reading: PDF (Excel 2011 source),One designed for hard-copy reading: PDF (Excel 2011 source),One designed for monochrome printing: PDF (Excel 2011 source), andOne designed for Red/Green color bindness -- a "Blue" theme PDF (Excel 2011 source). The color coded Legend / Keys helps provide guidance for your experience level.
HOWTO_Troubleshoot_SUDO – SSSD Check if configuration of sudo and SSSD cooperation is correct ¶ To check whether the basic configuration of sudo and SSSD is correct, check /etc/nsswitch.conf and /etc/sssd/sssd.conf files. /etc/nsswitch.conf must say that sss module is used for sudo service. Look for line like "sudoers: sss" (only SSSD is used), "sudoers: files sss" (local rules first, then SSSD) or similar.
Linux PAM Easy Guide - Like Geeks In the previous post, we talked about Linux iptables firewall, and some people asked about authentication. Today we will talk about the powerful framework in Linux used for authentication which is Linux PAM. PAM or Pluggable Authentication Modules are the management layer that sits between Linux applications and the Linux native authentication system. Linux-PAM Benefit Manipulating Strings Extracts substring from $string at $position. If the $string parameter is "*" or "@", then this extracts the positional parameters, starting at $position. Extracts $length characters of substring from $string at $position. The position and length arguments can be "parameterized," that is, represented as a variable, rather than as a numerical constant. Example 10-2. Generating an 8-character "random" string