In the current release of Cinelerra, the Linux Video editing tool, version 2.1 CV, you may get the error when starting up the program:
The following errors occurred:
void MWindow::init_shm0: WARNING:/proc/sys/kernel/shmmax is 0×2000000, which is too low.
Before running Cinelerra do the following as root:
echo “0x7fffffff”>/proc/sys/kernel/shmmax

Sure, you can run over to Terminal as Root and enter that command everytime your reboot and want to use Cinelerra, and yes, that’s 7 f’s. But why not make a more permanent change. This error message is just trying to say to allocate more memory space to Cinelerra. Cinelerra will be happy. Linux will be happy. You’ll be happy. So let’s go team!

Open terminal in super user mode, I just used the icon already on Debian, under Applications | System Tools | Terminal Server – Super User Mode and enter the following at the command prompt to make a backup of this file. You always make a backup, right!?

cp /etc/sysctl.conf /etc/sysctl.conf.backup

Now let’s edit this file. Enter this next:

nano /etc/sysctl.conf

At the very bottom of the file, add this line, and remember that’s 7 f’s, we’re talking memory size here. After adding this line, save and close the file, CTRL-X and then Y for yes to save it.

kernel/shmmax=0x7fffffff

Now, let’s put this file in action, at the command prompt enter:

sudo sysctl -p

Test by opening Cinelerra. Yay! No more annoying error message! Well, at least at startup.