How to Change Linux Account Password Through SSH: A Beginners’ Tutorial

People are sometimes given access to Linux/Unix and asked to change their initial passwords. But for beginners, changing a Linux/Unix password is not an easy task, especially when there is only SSH log on allowed to the Linux/Unix server. This post introduces how to change password of user USER on host HOST remotely using SSH. […]

How to Force Linux to Unmount a Filesystem Reporting “device is busy”

Linux may report “device is busy” when we try to umount a filesystem. This behavior is reasonable as it can help us avoid data loss by disallowing unmouting a filesystem when it is being used. But for situations when we are sure there is something wrong happened or we care not data lost such as […]

Three Methods of Executing Commands on Many Nodes in Parallel via SSH on Linux

It is common to execute commands on many nodes/hosts via SSH for managing a cluster of Linux servers. On Linux, there are many choices for this task. Generally, to run commands on many nodes, there are two modes: serial mode and parallel mode. In serial mode, the command is executed on the node one by […]

How to Keep Linux SSH Session Alive from Disconnecting – Server and Client Side Fixes

SSH is a very common tool for Linux/Unix platforms. One annoying problem when using SSH is that the connection may get disconnected if the SSH connection is idle for some time under common configurations. Users may run an infinite loop like while true; do uptime; sleep 30; done when there is no work to be […]

SSD Enabled For DreamHost Shared Hosting: Simple Performance Measurement

As you may know, SysTutorials is hosted by DreamHost and we are quite satisfied with DreamHost. Now, DreamHost turns to be the first big player that enables solid state drives (SSD) for its Linux-based shared hosting plan in the shared hosting market and we are happy to enjoy the improvement. SSD is common for VPS […]

Lazy Linux Admins Going to Server Rooms Less: Forced Reboot, Auto Reboot after Kernel Panic and Email Notification after Reboot

Having to go the the server room to reset servers is the most headache thing for admins managing a cluster of Linux servers in a remote site. Either you can ping the server but can not ssh to it, or you even can not ping it. There are various reasons that may cause a Linux […]

Improving ssh/scp Performance by Choosing Suitable Ciphers

Update on Oct. 9, 2014: You should be aware of the possible security problems of blowfish and it is suggested not to be used. Instead, you may consider ChaCha20 as suggested by Tony Arcieri. To use this with OpenSSH, you need to specify the Ciphers in your *.ssh/config* files as chacha20-poly1305@openssh.com possibly with another default […]