Changing $PATH variable

Question

I used this to add to PATH:

APXS2=/usr/local/apache/bin/apxs PATH=$PATH:/usr/local/apache/bin passenger-install-apache2-module

and my PATH now looks like this:

/usr/local/jdk/bin:/usr/kerberos/sbin:/usr/kerberos/bin:/usr/lib/courier-imap/sbin:/usr/lib/courier-imap/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/X11R6/bin:/root/bin:

Now I want to remove this I added. How to do this?

Answer 1

The best way might be to simply store a copy of the path before altering it.

PATH_BAK=$PATH
PATH=...
...
PATH=$PATH_BAK

Answer 2

Just log out, login again and your PATH will be reset.

Answer 3

If you forgot to create a backup you can use the substring removal/replace.

Substring Removal

${string#substring}

Substring Replace

${string/substring/replacement}

Please refer to this link http://www.museum.state.il.us/ismdepts/library/linuxguides/abs-guide/string-manipulation.html

Answer 4

Given /usr/local/apache/bin isn't in the '... my PATH now looks like this ...' - what do you think you added ? Assuming you're on bash or ksh - you didn't actually change the path because you didn't export it. So I doubt you need to remove anything.

E.g.

$ echo $PATH
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
$ PATH=$PATH:/foo /bin/ls
aFile
$ echo $PATH
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
$ # PATH did not alter

Versus:

$ echo $PATH
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
$ export PATH=$PATH:/foo
$ /bin/ls
aFile
$ echo $PATH
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/foo
$ #PATH modified.

So unless you exported the new PATH to the shell you're invoking the command from the PATH did not alter.