How to set the environment variable LD_LIBRARY_PATH in linux

Question

I have first executed the command: export LD_LIBRARY_PATH=/usr/local/lib

Then I have opened .bash_profile file: vi ~/.bash_profile. In this file, I put:

LD_LIBRARY_PATH=/usr/local/lib
export LD_LIBRARY_PATH

Then if the terminal is closed and restarted, typing echo $LD_LIBRARY_PATH displays no result.

How to set the path permanently?

Currycomb

Pointing it out the obvious here... If you just want to fix what you did, add a $, e.g. export LD_LIBRARY_PATH=$LD_LIBRARY_PATH – Milkfish

just run sudo ldconfig after that – Pythagoras

this might be silly but did you $ source ~/.bash_profile ? I tend to forget that. And then like @neckTwi said run ldconfig – Phaedra

Answer 1

You should add more details about your distribution, for example under Ubuntu the right way to do this is to add a custom .conf file to /etc/ld.so.conf.d, for example

sudo gedit /etc/ld.so.conf.d/randomLibs.conf

inside the file you are supposed to write the complete path to the directory that contains all the libraries that you wish to add to the system, for example

/home/linux/myLocalLibs

remember to add only the path to the dir, not the full path for the file, all the libs inside that path will be automatically indexed.

Save and run sudo ldconfig to update the system with this libs.

Germanic

Sorry for not mentioning the distribution. Its Fedora 16 – Currycomb

you can use this solution for Fedora, the solution suggested by Joachim Pileborg it's useful if you decide to limit the view of this libs to 1 specific user, if you you want a system wide lib tou should use my solution. It all depends on what you are looking for. – Germanic

Is this really the right way? Suppose you have multiple users building local libraries, and you've added both of them to /etc/ld.so.conf.d. Now user A can link to user B's local libraries. Not good. – Bibliology

/usr/local/lib is usually already there, so there's no need to edit any files, just sudo ldconfig. – Dm

Works on xubuntu 16.04 – Subsist

Strange it worked with all of you guys, however it didn't work for me, while the export LD_LIBRARY_PATH .... way works !! – Centurion

This was a lifesaver to resolve this problem: 'ImportError: libpq.so.5: cannot open shared object file: No such file or directory error in SageMaker when trying to import psycopg2. Found the path using: $ find ~/ -name libpq.so.5 Then used @Germanic suggestion: sudo vim /etc/ld.so.conf.d/pyscopg.conf followed by SageMaker location for libpg.so.5: /home/ec2-user/anaconda3/envs/JupyterSystemEnv/lib/ then ran sudo ldconfig. Magic. – Biographer

Man!That saved my life. I tried to add LD_LIBRARY_PATH into environement, .profile, .bashrc ... And the system didn't see the libs.THis one resolved it.Thanks! Ubuntu 18.04 – Burks

@Bibliology it would be better if i could have a ld.so.conf somewhere in my home directory. Is that possible ? – Pontonier

This didn't work for me, because afterwards, even after rebooting, echo $LD_LIBRARY_PATH is empty... (Ubuntu 20.04) – Mabelmabelle

Answer 2

Keep the previous path, don't overwrite it:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/your/custom/path/

You can add it to your ~/.bashrc:

echo 'export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/your/custom/path/' >> ~/.bashrc

Cuisine

Don't ask me why, but this did not work, until I made this small change: mv ~/.bashrc ~/.bash_profile with otherwise the same code and same file privileges. It then worked. This is on Ubuntu 20.04.1 LTS. Without this file rename, LD_LIBRARY_PATH would still be empty on re-login. .bashrc was rwx for user, so it should execute fine. Executing it manually would also not set LD_LIBRARY_PATH (somewhat expected), and sourcing it (. ./.bashrc) did set it. Very odd, and I expect it's Ubuntu 20.04.1 LTS specific. – Pollster

Adding it to .bashrc may make the variable polluted with the value on each new invocation. Consider ~/.bash_profile , ~/.profile , or /etc/profile instead. – Immigrate

Answer 3

Add

LD_LIBRARY_PATH="/path/you/want1:/path/you/want/2"

to /etc/environment

See the Ubuntu Documentation.

CORRECTION: I should take my own advice and actually read the documentation. It says that this does not apply to LD_LIBRARY_PATH: Since Ubuntu 9.04 Jaunty Jackalope, LD_LIBRARY_PATH cannot be set in $HOME/.profile, /etc/profile, nor /etc/environment files. You must use /etc/ld.so.conf.d/.conf configuration files.* So user1824407's answer is spot on.

Underling

Wow, I looked at that page several times and overlooked that. Thanks for spotting it and bringing it to our attention. – Schopenhauer

Ubuntu is a special case here. Ubuntu's view is that all users want the same libraries and that there is only one place for each library (read discussion in Launchpad bug #366728). However, on multi-user research or development systems, you want each users to be able to have their own versions of libraries. Most Linux distributions allow this and have done so for many years. – Michelemichelina

Spent 4 hours trying to figure why I can set PATH and PKG_CONFIG_PATH, but not LD_LIBRARY_PATH. I can't even. – Mom

@JoachimWagner Yes, this is correct, and why conda and/or bioconda or virtenv is now a preferred method on invoking a particular program with special environmental variables. By using encased environments, inadvertently setting the LD_LIBRARY path will not have systemic issues/problems. – Ewen

Answer 4

Alternatively you can execute program with specified library dir:

/lib/ld-linux.so.2 --library-path PATH EXECUTABLE

Read more here.

Louden

Yeah I agree with spt025 - I never knew that trick was possible. I feel there is so much sort of hidden away stored in some archaic manpage at best ... so StackOverflow is really helpful for THAT particular kind of information. – Curium

Answer 5

The file .bash_profile is only executed by login shells. You may need to put it in ~/.bashrc, or simply logout and login again.

Baring

Thank you Joachim Pileborg. I have reboot the system and now its path is set permanently. – Currycomb

Answer 6

For some reason no one has mentioned the fact that the bashrc needs to be re-sourced after editing. You can either log out and log back in (like mentioned above) but you can also use the commands: source ~/.bashrc or . ~/.bashrc.

Macegan

Answer 7

Put export LD_LIBRARY_PATH=/usr/local/lib in ~/.bashrc [preferably towards end of script to avoid any overrides in between, Default ~/.bashrc comes with many if-else statements]

Post that whenever you open a new terminal/konsole, LD_LIBRARY_PATH will be reflected

Mitrailleuse

Sorry for not mentioning the distribution. Its Fedora 16 – Currycomb

Answer 8

1. Go to the home folder and edit .profile

2. Place the following line at the end

   export LD_LIBRARY_PATH=<your path>

3. Save and Exit.

4. Execute this command

   sudo ldconfig

Holster

Answer 9

You could try adding a custom script, say myenv_vars.sh in /etc/profile.d.

cd /etc/profile.d
sudo touch myenv_vars.sh
sudo gedit myenv_vars.sh

Add this to the empty file, and save it.

export LD_LIBRARY_PATH=/usr/local/lib

Logout and login, LD_LIBRARY_PATH will have been set permanently.

Forbiddance

Awesome answer. Best choice for me to export a path every time during system initialisation and much safer than physically editing /etc/bashrc – Heavyarmed

Answer 10

I do the following in Mint 15 through 17, also works on ubuntu server 12.04 and above:

sudo vi /etc/bash.bashrc 

scroll to the bottom, and add:

export LD_LIBRARY_PATH=.

All users have the environment variable added.

Behindhand

Answer 11

In Ubuntu 20.04 Linux this is just not obvious and straight forward as it should be.

I will attempt to make it simple for anyone who is pulling out their hair just like I was with my Ubuntu 20.04.3 Linux.

Start by identifying the path where your library files' folder is located. In my case, the *.so files that I was working with were located in a folder called libs and this folder's path in my Ubuntu box is /usr/lib

So now I want to add the path /usr/lib to LD_LIBRARY_PATH such that when I run echo $LD_LIBRARY_PATH in my Ubuntu terminal I will be able to see the path /usr/lib echoed as shown below;

joseph$ echo $LD_LIBRARY_PATH
:/usr/lib

Here are the steps I used

1. Open terminal in Ubuntu 20.04 Linux box
2. Change path to /etc/ld.so.conf.d/ by running cd /etc/ld.so.conf.d/
3. Create a file with a *.conf extension at the end with a text editor like e.g. vim or gedit in my case I created it as follows sudo gedit my_project_libs.conf
4. Inside the .conf file that I created named my_project_libs.conf I added the path to my libs by adding this line export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib
5. Thereafter, I then run gedit ~/.bash_profile to open the ~/.bash_profile file so that I can add inside it this line export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib which includes the path to the folder with my libraries /usr/lib that I want included in LD_LIBRARY_PATH
6. I also ran gedit ~/.bashrc to open the ~/.bashrc file so that I can add inside it this line export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib which includes the path to the folder with my libraries /usr/lib that I want included in LD_LIBRARY_PATH
7. When you are done adding the line in step 5, save and close.
8. In your terminal, type the following sudo ldconfig and press enter on your keyboard. Close all your open terminals that you were using then open a new terminal session and run echo $LD_LIBRARY_PATH If you see the path you added is echoed back, you did it right.

In my case, this is what I see :/usr/lib when I run echo $LD_LIBRARY_PATH in my newly opened Ubuntu terminal session

joseph$ echo $LD_LIBRARY_PATH
:/usr/lib

That's how I got it to work for me in my Ubuntu 20.04.3 Linux box.

Heavyarmed

Answer 12

Everyone seems to be missing the forest for the trees.

The real answer is that '~/.bash_profile' is by default only sourced for LOGIN SHELLS.

The bash config file you are probably looking for if you are starting and closing terminals from your desktop GUI is '~/.bashrc', which is the file sourced by default when starting interactive, non-login shells.

https://apple.stackexchange.com/questions/51036/what-is-the-difference-between-bash-profile-and-bashrc

Dextrous