Commands by tkunz (4)

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Find usb device in realtime
Using this command you can track a moment when usb device was attached.

resume other user's screen session via su, without pty error
Normally, if you su to another user from root and try to resume that other user's screen session, you will get an error like "Cannot open your terminal '/dev/pts/0' - please check." This is because the other user doesn't have permission for root's pty. You can get around this by running a "script" session as the new user, before trying to resume the screen session. Note you will have to execute each of the three commands separately, not all on the same line as shown here. Credit: I found this at http://www.hjackson.org/blog/archives/2008/11/29/cannot-open-your-terminal-dev-pts-please-check.

recursive search and replace old with new string, inside files
Using -Z with grep and -0 with xargs handles file names with spaces and special characters.

strip config files of comments
some configuration files, particularly those installed by default as part of a package, have tons of comment lines, to help you know what's possible to configure, and what it means. That's nice, but sometimes you just want to see what specifically what _has_ been configured. That's when I use the above snippet, which I save as a bash alias 'nocom' (for 'no comments'). Apache default config files are perfect examples of when/why this script is handy.

Let your computer lull you to sleep
Can change language and speed, see espeak man page for options. (Install espeak in your linux distro via yum or apt-get) For insomniacs you may need to enclose in a while true; do ...; done loop ;)

dd with progress bar and statistics to gzipped image

Get your external IP address if your machine has a DNS entry
Easy way to see your real external IP

Another way to calculate sum size of all files matching a pattern
Here the pattern is '*.jar', you could pass in any pattern. Another, maybe nicer way to do this is http://www.commandlinefu.com/commands/view/1921/summarise-the-size-of-all-files-matching-a-simple-regex You could replace sed with tr

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

wrap long lines of a text
wraps text lines at the specified width (90 here). -s option is to force to wrap on blank characters -b count bytes instead of columns


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