Commands by skygreg (7)

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More precise BASH debugging

Monitor logs in Linux using Tail
Works in Ubuntu, I hope it will work on all Linux machines. For Unixes, tail should be capable of handling more than one file with '-f' option. This command line simply take log files which are text files, and not ending with a number, and it will continuously monitor those files. Putting one alias in .profile will be more useful.

count processes with status "D" uninterruptible sleep

Short one line while loop that outputs parameterized content from one file to another
The above is an example of grabbing only the first column. You can define the start and end points specifically by chacater position using the following command: $ while read l; do echo ${l:10:40}; done < three-column-list.txt > column-c10-c40.txt Of course, it doesn't have to be a column, or extraction, it can be replacement $ while read l; do echo ${l/foo/bar}; done < list-with-foo.txt > list-with-bar.txt Read more about parameter expansion here: http://wiki.bash-hackers.org/syntax/pe Think of this as an alternative to awk or sed for file operations

Create strong, but easy to remember password
Why remember? Generate! Up to 48 chars, works on any unix-like system (NB: BSD use md5 instead of md5sum)

gvim in full screen (execute again to toggle full screen on/off)
Only under linux. Requires Gvim compiled with "clientserver" functionality and wmctrl command installed on system. Instead of servername can be used the current edited file name. Put it in a function and map it for get rid of "Press a key" after execution.

Processes by CPU usage

find an unused unprivileged TCP port
Some commands (such as netcat) have a port option but how can you know which ports are unused?

Create commands to download all of your Picasaweb albums
Create commands to download all of your Picasaweb albums Install Googlecl (http://code.google.com/p/googlecl/) and authenticate first.

How to trim a video using ffmpeg
Will trim the video to 4 seconds starting from the beginning. The -vcodec , -acodec options are required so that ffmpeg knows in what video/audio format you want for the new video.


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