Ulimit, Soft Limits and Hard Limits in Linux

Last Updated : 26 Nov, 2020

ulimit is admin access required Linux shell command which is used đồ sộ see, phối, or limit the resource usage of the current user. It is used đồ sộ return the number of open tệp tin descriptors for each process. It is also used đồ sộ phối restrictions on the resources used by a process.

Syntax:

To kiểm tra the ulimit value use the following command:

ulimit -a

Working with ulimit commands:

1. To display maximum users process or for showing maximum user process limit for the logged-in user.

ulimit -u

2. For showing the maximum tệp tin size a user can have.

ulimit -f

3. For showing maximum memory size for the current user.

ulimit -m

4. For showing maximum memory size limit.

ulimit -v

What are Soft limits and Hard limits in Linux? 

The soft limits are the limits which are allocated for actual processing of application or users while the Hard limits are nothing but an upper bound đồ sộ the values of soft limits. Hence,  

(soft limits <= hard limit)

Working with Hard and Soft limit values:

1. For displaying the Hard limit. Hard limits are a restriction đồ sộ the maximum value of soft limits

ulimit -Hn

2. For displaying Soft Limit. The soft limits are the limits that are there for processing.

ulimit -Sn

3. To change Soft Limit values:

sysctl -w fs.file-max=

Note: Replace with the value you want đồ sộ phối for the soft limit and also remember size can not exceed the Hard Limit!

4. Displaying current Values for opened files

cat /proc/sys/fs/file-max