=====unix Keyword 2===== shabang ====Definition==== A **shabang** is this: //#!// The **shabang** is used to read the following test on the first line after it to determine what interpreter the user would like to... use. Some example of interpreters (Taken directly from http://en.wikipedia.org/wiki/Shebang_(Unix): * #!/bin/bash -- Execute the file using sh, the Bourne shell, or a compatible shell * #!/bin/csh -- Execute the file using csh, the C shell, or a compatible shell * #!/usr/bin/perl -T -- Execute using Perl with the option for taint checks * #!/usr/bin/php -- Execute the file using the PHP command line interpreter * #!/usr/bin/python -0 -- Execute using Python with optimizations to code * #!/usr/bin/ruby -- Execute using Ruby ====References==== * http://en.wikipedia.org/wiki/Shebang_(Unix) =====unix Keyword 2 Phase 2===== PATH environment variable ====Definition==== The $PATH variable specifies a list of one or more directory names separated by colons. The /bin, /usr, and /local directories are typically included in most users' $PATH settings. The current directory is sometimes included, allowing programs in the current directory to be executed. Superuser (root) accounts as a rule are not include in $PATH, however, in order to prevent the accidental execution of scripts in the current directory. When a command name is specified by the user or an exec call is made from a program, the system searches through $PATH, examining each directory from left to right in the list, looking for a filename that matches the command name. Once found, the program is executed as a child process of the command shell or program that issued the command. ====References==== http://en.wikipedia.org/wiki/PATH_%28variable%29 ====Demonstration==== The following is an example of a **$PATH**: lab46:~/src/opus/opus2$ The **$PATH** The //home// directory (~/) is the beginning of this specified **$PATH**, followed by the //src// directory, then the //opus// directory, and lastly the //opus2// directory.