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This article shows you what are the common query handle commands in Linux, which are concise and easy to understand, which can definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

Query the total number of handles occupied by command processes lsof-n | wc-l to see which process occupies the most handles lsof-n | awk'{print $2}'| sort | uniq-c | sort-nr | more

The first column is the number of occupied handles; the second column is the process number PID

| query the occupied handle of a process lsof | grep PID |

First column: process name second column: PID third column: process owner fourth column: file descriptor fifth column: file type

Linux setting handle command method 1

Step 1: modify the linux system parameters. Vi / etc/security/limits.conf add

* soft nofile 65535 * hard nofile 65535

Here * means all users, but some systems do not recognize them and require specific user names, such as:

Root soft nofile 65535 root hard nofile 65535

Step 2: edit the etc/pam.d/login to make sure it looks like the following line:

Session required pam_limits.so

Step 3: save after modification, log out of the current user, and log in again

Step 4: verify. Use the ulimit-Hn and ulimit-Sn commands to view the current process user's hard and soft limits, respectively.

Or after the current user starts a program, through cat / proc//limits (pid belongs to that process, or the pid of any of its child processes)

Method 2 ulimit-HSn 65536

Simply execute this command, which is valid only in the current reply. If you want to save it permanently, you can modify the .bash _ profile file and / etc/profile to add the above command to the end.

Appendix

Ulimit-a view the current user's file handle restrictions

Ulimit-a

Limit the number of handles at the user level.

Modify / etc/security/limits.conf to add the following code: user name (or * for all users) soft nofile 65535

User name hard nofile 65535 has two restrictions, one is the soft soft limit, when the number exceeds the soft limit, the system will give warning warning, but when the hard hard limit is reached, the system will reject or exception. After modification, you may need to restart shell to take effect.

The number of handles at the system level is limited.

Sysctl-w fs.file-max 65536

Or

Echo "65536" > / proc/sys/fs/file-max

The function of the two is the same, the former changes the kernel parameters, while the latter directly acts on the corresponding files of the kernel parameters on the virtual file system (procfs, psuedo file system). You can view the new restrictions with the following command

Sysctl-a | grep fs.file-max

Or

Cat / proc/sys/fs/file-max

Modify kernel parameters

/ etc/sysctl.confecho "fs.file-max=65536" > > / etc/sysctl.confsysctl-p

View the system total limit command:

Cat / proc/sys/fs/file-max

View the number of file handles currently used by the entire system command:

Cat / proc/sys/fs/file-nr

See which handles are opened by a process:

Lsof-p pid

A process opened several handles:

Lsof-p pid | wc-l

You can also see what process a directory / file is occupied by, displaying all process information about the directory or file that has been opened:

The above contents of lsof path/filename are the commands of common query handles in Linux. Have you learned any knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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