When parsing log files sed is not the go-to tool for most techs, but it offers a pretty neat feature: the ability to easily search a log file for a specific date/time range. Pattern Matching sed -n ‘/Dec 30 13:00/p’ /var/log/messages Date Range Matching sed -n ‘/Dec 30 13:00/,/Dec 30 14:00/p’ /var/log/messages Change Delimiters If … [Read more…]
Inevitably every Linux administrator will eventually have to alter permissions and owerships, perhaps even FACLs. But what happens when your changes go awry? The problem is amplified if you were making changes recursively! Backup Permissions Fortunately there is a pretty simple method to backup the permissions, ownerships, and FACLs: getfacl -pR /path/to/backup > /root/perms.bak NOTE: … [Read more…]
Bind mounts in Linux allow you to mount one part of the file hierarchy somewhere else. I highly recommend using bind mounts in chrooted environment as it can simplify user access control. Creating Bind Mounts Bind mounts were added in kernel 2.4.0, so older systems will not support it. Run uname -r to verify your … [Read more…]
I tend to spend quite a bit of my time on a command line, so I am always looking for little ways to make my life easier. Because of that, this post will be a bit of a living document that I plan to occasionally update as I discover more handy tricks. This is not … [Read more…]
Linux is chock-full of documentation, the challenge however is knowing where to find that documentation. One of the first things that every Linux user ought to learn is how to view the manual pages, man <command>, but there is more to know. The man pages are divided into 9 sections: Executable programs or shell commands … [Read more…]