
Chapter 8. Open system servers - Linux for xSeries 273
Using the sysctl commands
The sysctl commands use the names of files in the /proc/sys directory tree as parameters.
For example, to modify the shmmax kernel parameter, you can display (using cat) and
change (using echo) the file /proc/sys/kernel/shmmax:
#cat /proc/sys/kernel/shmmax
33554432
#echo 33554430 > /proc/sys/kernel/shmmax
#cat /proc/sys/kernel/shmmax
33554430
However, using these commands can easily introduce errors, so we recommend that you use
the sysctl command because it checks the consistency of the data before it makes any
change. For example:
#sysctl kernel.shmmax
kernel.shmmax = ...