How to list start and end of a partition by the sectors in parted on Linux? The default behavior seems be listing the start and end by bytes in parted. # parted /dev/sdc print Model: Innostor IS888 ext. HDD (scsi) Disk /dev/sdc: 2000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End […]
Posts tagged sysadmin
11 posts in total.
How to pause and resume the execution of a process on Linux?
How to pause the execution of a process on Linux so that the CPU can be freed? Later, if the node is idle again, how to resume the execution? There are 2 signals related to stopping (pausing) and continuing (resuming) processes: Stop Default action is to stop the process. Cont Default action is to continue […]
How to allow root access to NFS?
On local filesystems, root usually has full access (read/write) to directories/files inside of it. But for NFS directory mounted from nework, root usually has no permission to write to it. How to make root act as on local directory for NFS directory? The reason that NFS directory is non-accessible to root is likely “root_squash”. It […]
How to change a user’s username on Linux?
I want to rename a user’s username on Linux. For example, rename user u1 to user1. How to change a user’s username on Linux? You can use the usermod command to modify the user’s info. For changing the user name, you can use the -l option: -l, –login NEW_LOGIN The name of the user will […]
How do I force Linux to unmount a filesystem?
Some time, Linux fails to unmount a filesystem reporting “device is busy”. I understand that this helps avoid data lost by disallowing unmouting a filesystem when it is being used. But for some situations, I am sure there is something wrong happened or I care not data lost, such as a NFS mounting while the […]
How to force umount a NFS directory on Linux?
The NFS server is down. It is reported “Stale NFS file handle”. I tried ‘umount’ and ‘umount -f’. But neither succeeded. # umount /mnt/store umount.nfs: /mnt/store: Stale NFS file handle # umount -f /mnt/store umount.nfs: /mnt/store: Stale NFS file handle How to force umounting the NFS without rebooting the Linux server? I usually have to […]
How to deactivate a LVM logical volume on Linux?
How to deactivate a LVM logical volume activated by #vgchange -aay on Linux You may need to make a LVM volume group inactive and thus unknown to the kernel. To deactivate a volume group, use the -a (–available) argument of the vgchange command. To deactivates the volume group vg, use this command # vgchange -a […]
How to redirect STDOUT of sudo command on Linux and write to file as root?
A try like the following command failed $ sudo echo “echo hello” > /usr/local/bin/hello with an message bash: /usr/local/bin/hello: Permission denied It seems the writing to the file is executed under the non-root user. How to redirect STDOUT of sudo command on Linux and write the content to the file (/usr/local/bin/hello here) as root? You […]
How to allow non-root users on Linux to mount and unmount disks?
On a Linux box, we may allow non-root users mount and umount certain disks, such as /dev/sde1. How to allow non-root users on Linux to mount and unmount disks? Please check the tutorial at Controlling Filesystem Mounting on Linux by Playing with /etc/fstab: Allow non-root users to mount and unmount filesystems. Answered by Eric Z […]
How to find all available versions of a package in dpkg, apt-get or aptitude?
How to find all available versions of a package in dpkg, apt-get or aptitude? To list available versions of a package: apt-cache showpkg <package-name> For example, to check all versions of thunderbird: $ sudo apt-cache showpkg thunderbird Package: thunderbird Versions: 1:31.1.1+build1-0ubuntu0.14.04.1 (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty-updates_main_binary-amd64_Packages) (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_main_binary-amd64_Packages) Description Language: File: /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty_main_binary-amd64_Packages MD5: 68ed1001b79d708ad48956a0c129114d Description Language: en File: /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty_main_i18n_Translation-en MD5: […]
How to find which hard drives a LVM volume uses?
How to find which hard drives a LVM volume uses to decide which volume will be affected if a disk failes. You can use lvdisplay with the –maps option to display the the mapping of logical extents to physical volumes and physical extents: # lvdisplay –maps To map physical extents to logical extents, use # […]