Adding a path to the .bashrc file?

Question

At the moment I am trying to add a path for ns-2 to my .bashrc file, I have installed the ns-allinone-2.34 but the command ns gives the result: command not found when entered into the shell.

Here is what my .bashrc file currently looks like, I edited it using gedit:

# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi


# User specific aliases and functions
export PATH=/home/michael/ns-allinone-2.34/bin/ns:/home/michael/ns-allinone-2.34/bin/nam:$PATH

Can someone please explain why this isn't working or what a possible solution may be? I am using fedora 17.

Is this the binary or the directory : /home/michael/ns-allinone-2.34/bin/ns ? It needs to be the *directory* containing the binary — Brian Agnew, Nov 29 '12 at 17:19
AH that fixed it I was using the binary not the directory, I deleted the ns and nam off the end and it is now working! — user1825241, Nov 29 '12 at 17:24

score 46 · Answer 1 · edited Jun 13 '16 at 10:02

46

Also if you export path like this, you want to keep old PATH as well, therefore include it as well.

export PATH=$PATH:/home/michael/ns-allinone-2.34/bin/

edited Jun 13 '16 at 10:02

Andrew Tobilko

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answered Nov 29 '12 at 18:07

user1830432

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He did, it's at the end, just as it should be. – tripleee Nov 29 '12 at 19:25
1

Oh, you are right, I didn't scroll there and expected original PATH to be in the beginning... – user1830432 Nov 29 '12 at 22:12
what's the exact difference between this answer and the accepted one? I mean, what happens if "$PATH:" is not added before bin's path? – Cristian Todea Dec 02 '16 at 09:07
@Todea the path gets searched in the order given. So if you put the existing path at the end, any same-named executables will be called instead of the normal ones. This is not usually what you want, and becomes a security hole if the folder has weaker perms than the system command folders: someone can get you to run an arbitrary command just by creating a file in there called "ls". But then, we shouldn't be running exes from world-writable folders anyway :) So, it's handy when you want to override the default system commands, but aliases won't cut it. – Dewi Morgan Jun 10 '17 at 19:22

score 13 · Accepted Answer · edited Nov 08 '16 at 20:04

13

The PATH should contain the directory for the binaries, not the binaries themselves.

For example, in the above:

export PATH=/home/michael/ns-allinone-2.34/bin/ns:..

should actually be:

export PATH=/home/michael/ns-allinone-2.34/bin:...

edited Nov 08 '16 at 20:04

CaptJak

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answered Nov 29 '12 at 17:29

Brian Agnew

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I did down voted this answer by mistake.. not sure how to revert it.. help me please :) – Maystro Oct 13 '16 at 14:32
Just press the same arrow button again, I think. – Brian Agnew Oct 13 '16 at 15:26
Nope.. It says "Your vote is now locked in unless this answer is edtied" – Maystro Oct 13 '16 at 15:31
@Maystro your downvote is justified. This could potentially erase all previous PATH. See the second answer below – Binu Jasim May 13 '17 at 23:28
@BinuJasim - Can you please explain how *amending* a PATH variable to the correct directory and removing the erroneous reference to the binary does not work ? – Brian Agnew May 16 '17 at 18:50
@Brian I accidentally deleted all my previously set PATH by executing your command. export PATH=$PATH:/home/michael/ns-allinone-2.34/bin/ will keep the previous PATH. But technically you answered the question correctly. – Binu Jasim May 17 '17 at 02:45
You understand the above says 'for example'? – Brian Agnew May 17 '17 at 07:29

Adding a path to the .bashrc file?

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