ulimit -> a Linux Command : To limit user resources

The shell contains a built-in command to limit file sizes, ulimit, which can also be used to display limitations on system resources. A second method for limiting the potential impact of runaway processes is to set limits on a per process basis. This can be achieved by setting the ulimit command in /etc/profile.

The ulimit command allow to limit system-wide resource use. This can help a lot in system administration, e.g. when a user starts too many processes and therefore makes the system unresponsive for other users.

-bash-3.00$ ulimit -a

core file size (blocks, -c) 0

data seg size (kbytes, -d) unlimited

file size (blocks, -f) unlimited

pending signals (-i) 1024

max locked memory (kbytes, -l) 32

max memory size (kbytes, -m) unlimited

open files (-n) 1024

pipe size (512 bytes, -p) 8

POSIX message queues (bytes, -q) 819200

stack size (kbytes, -s) 10240

cpu time (seconds, -t) unlimited

max user processes (-u) 274432

virtual memory (kbytes, -v) unlimited

file locks (-x) unlimited

-bash-3.00$

Let's say, if you got an error like - Configuration Error: nofiles is set to '1024' but minimum required is '2048' then you can change using the below command -

-bash-3.00$ ulimit -n 4096