I recently used a screen capture program to record a video of some actions in Firefox. When the video was complete, the Duration was incorrect. Windows Media Player doesn’t seem to mind and happily played the entire video even though the duration property was 16 seconds and the actual duration was 31 seconds. When I […]

Check the number of lines in a text file using the wc command, which stands for “word count”. $ wc -l access.log146330 access.log We’re way over our limit. We’ll need to split this into 3 segments. We’ll use the split utility to do this. $ split -l 60000 access.log $ ls -l total 79124 -rw-rw-r– […]

If you need to prevent a package from upgrading during ‘apt-get upgrade’, you need to put that package on hold: $ sudo apt-mark hold package_name When you run ‘apt-get upgrade’ with a package on hold, the output will look like this: $ sudo apt-get upgrade Reading package lists… Done Building dependency tree Reading state information… […]

You should always leave the current kernel and one previous kernel in place on your system. The previous kernel is needed if an update to the current kernel leaves your system unable to boot. You will be able to boot the previous kernel using the advanced options of the grub boot menu. Show current kernel […]

The du (i.e., disk usage) command reports the sizes of directory trees inclusive of all of their contents and the sizes of individual files: -h, –human-readable print sizes in human readable format (e.g., 1K 234M 2G) -s, –summarize display only a total for each argument -x, –one-file-system skip directories on different file systems The sort […]

List files, filter by size, print only size+space+path, and sort by size only, descending order: size=10485760 tar tvf some.tar.gz \ | awk -v size=”$size” ‘$3 >= size {print $3″ “$6}’ \ | sort -t’ ‘ -k1,1nr