ulimit parameters explain

ulimit parameters through a number of options to manage different types of system resources. In this section, we will explain the use of these parameters.

ulimit command format is: ulimit [options] [limit]

Meaning of specific options and a simple example can refer to the following table.

Table 1. Ulimit parameter descriptions

Options [options]	Meaning	Example
-H	Set the hard resource limit, once set can not increase.	ulimit - Hs 64; limited hardware resources, the thread stack size is 64K.
-S	Set the soft resource limit settings can be increased, but not more than hard-resource settings.	ulimit - Sn 32; soft resource limit, 32 file descriptors.
-A	Show all current limit information.	ulimit - a; show all current limit information.
-C	Maximum core file size, in blocks as a unit.	ulimit - c unlimited; the generated core file size without limit.
-D	The largest process data segment size in Kbytes units.	ulimit-d unlimited; of the process data segment size without limit.
-F	The maximum process can create a file to blocks of flats.	ulimit - f 2048; limit process can create the maximum file size is 2048 blocks.
-L	Maximum locked memory size in Kbytes units.	ulimit - l 32; limit the maximum locked memory size 32 Kbytes.
-M	Maximum memory size to Kbytes units.	ulimit - m unlimited; no limit on the maximum memory.
-N	The maximum number of file descriptors can open.	ulimit - n 128; limit the maximum to 128 file descriptors.
-P	Pipe buffer size in Kbytes units.	ulimit - p 512; limit the size of pipe buffer is 512 Kbytes.
-S	Thread stack size in Kbytes units.	ulimit - s 512; limit thread stack size is 512 Kbytes.
-T	Maximum CPU utilization time in seconds.	ulimit - t unlimited; for maximum CPU usage time without restrictions.
-U	Maximum available number of user processes.	ulimit - u 64; restrict users may use up to 64 process.
-V	Process the maximum amount of virtual memory, in Kbytes units.	ulimit - v 200000; limit the maximum amount of virtual memory is 200000 Kbytes.