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Sysctl

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'''sysctl''' is used to get/set various kernel and kernel module parameters
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'''sysctl''' is used to get/set various kernel and kernel module parameters.
  
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To get the value of a kernel parameter:
  
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[root@splat ~]# '''sysctl hw.physmem'''
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hw.physmem: 130453504
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 +
To set the value of a kernel parameter:
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[root@splat ~]# '''sysctl net.link.ether.bridge=0'''
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net.link.ether.bridge: 1 -> 0
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Please note that some parameters are read-only and cannot be changed.
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You can use the '''-a''' parameter to list all '''sysctl''' variables. Coupled with [[grep]] this makes a great way to find the '''sysctl''' variable you're looking for.
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[root@splat ~]# '''sysctl -a | grep mem'''
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vm.zone_kmem_pages: 182
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vm.zone_kmem_kvaspace: 14725120
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vfs.ufs.dirhash_maxmem: 2097152
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vfs.ufs.dirhash_mem: 292312
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hw.physmem: 130453504
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hw.usermem: 107544576
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Be careful when editing '''sysctl''' values. Invalid or incorrect settings could cause severe problems with your system.
  
 
[[Category:System Commands]]
 
[[Category:System Commands]]

Latest revision as of 10:55, 27 July 2005

sysctl is used to get/set various kernel and kernel module parameters.

To get the value of a kernel parameter:

[root@splat ~]# sysctl hw.physmem
hw.physmem: 130453504

To set the value of a kernel parameter:

[root@splat ~]# sysctl net.link.ether.bridge=0
net.link.ether.bridge: 1 -> 0

Please note that some parameters are read-only and cannot be changed.

You can use the -a parameter to list all sysctl variables. Coupled with grep this makes a great way to find the sysctl variable you're looking for.

[root@splat ~]# sysctl -a | grep mem
vm.zone_kmem_pages: 182
vm.zone_kmem_kvaspace: 14725120
vfs.ufs.dirhash_maxmem: 2097152
vfs.ufs.dirhash_mem: 292312
hw.physmem: 130453504
hw.usermem: 107544576

Be careful when editing sysctl values. Invalid or incorrect settings could cause severe problems with your system.

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