Linux

SSH

Description	Command
Create private/public SSH key file using 2048 bit encryption and with a comment. The command creates files under ~/.ssh folder.	ssh-keygen -b 2048 -C user@host.domain
Push public SSH key to a server	ssh-copy-id -p 41111 -i ~/.ssh/id_rsa.pub mhan@remote.server.com

Disk

LVM

Physical volume

Initialize for use as LVM physical volume.

$ pvcreate /dev/sdb1

Scanning for block devices.

$ lvmdiskscan

Display the physical volumes.

$ pvdisplay

Show all physical devices.

$ pvscan

Prevent allocation of physical extents on the free space of one or more physical volumes. This may be necessary if there are disk errors, or if you will be removing the physical volume.

$ pvchange -x n /dev/sdb1

Resize.

$ pvresize

Remove LVM label.

$ pvremove

Volume group

Create a volume group.

$ vgcreate vg1 /dev/sdb1 /dev/sdc1

Add a physical volume to a volume group.

$ vgextend vg1 /dev/sdd1

Display volume group.

$ vgdisplay new_vg

Scan disks for volume groups.

$ vgscan

Remove a physical volume from a volume group.

$ vgreduce group_name /dev/sdc1

Change parameters of a volume group. Change the maximum number of logical volumes of volume group vg00 to 128.

$ vgchange -l 128 /dev/vg00

Activate or deactivate a volume group.

$ vgchange -a n my_volume_group

Remove a volume group.

$ vgremove officevg

Split the physical volumes of a volume group and create a new volume group.

$ vgsplit bigvg smallvg /dev/ram15
Volume group "smallvg" successfully split from "bigvg"

Merge the inactive volume group my_vg into the active or inactive volume group databases giving verbose runtime information.

$ vgmerge -v databases my_vg

Change the name of a volume group.

$ vgrename vg02 my_volume_group

File

Permissions

Letter	Number
r	4
w	2
x	1
rw-	6
r-x	5
rwx	7