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--- nix:pathvars [2020/01/06 15:28] – kauffman
+++ nix:pathvars [2020/01/06 15:49] – kauffman
@@ Line 63: / Line 63: @@
+===== Manipulating the PATH variable =====
+Your shell will allow you manipulate the order in which these paths appear. It's as simple as setting a variable.
+For the following examples I assume you are using the bash shell, which is the default in CS. The concept will translate to other shells, though the syntax may be different.
+A common example to manipulate your path is if you have written a script and you'd like to invoke it without providing the full path:
+Lets create the directory ''%%bin%%'' in the root of our home directory:
+<code>
+user@linux1:~$ mkdir ~/bin
+</code>
+We will place our example script that echo's 'Hello World!' into ''%%~/bin/hello%%''
+<code>
+#!/bin/bash
+echo 'Hello World!'
+</code>
+and make it executable.
+<code>
+user@linux1:~$ chmod +x ~/bin/hello
+</code>
+Now that we have our executable ''%%hello%%'' we'd like to be able to call it without prepending the path like this: ''%%~/bin/hello%%''
+As you may have guessed we will want to add (pre or postpend) ''%%~/bin%%'' to our ''%%PATH%%'' variable.
+==== The reason you are here ====
+<code>
+$ export PATH=$PATH:~/bin
+</code>
+To test we will need the shell to reevaluate $PATH.
+<code>
+$ hash -r
+</code>
+Now we can see that ''%%hello%%'' is in our path and we can execute it without the full path.
+<code>
+user@linux1:~$ which hello
+/home/user/bin/hello
+user@linux1:~$ hello
+Hello World!
+</code>
+==== Making the change permanent ====
+Add the following line to a file called ''%%~/.bash_profile%%''.
+   export PATH=$PATH:$HOME/bin
+This will postpend our custom path to the search path every time we launch a bash login shell.
+If you'd like to prepend just move your path in front of ''%%$PATH%%''. Just make sure each path is separated by a colon ''%%:%%''.
+    export PATH=$HOME/bin:$PATH