Commands by prasadwani (2)

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Show a prettified list of nearby wireless APs

Determine the version of a specific package with RPM
In this case, I'm getting the package version for 'redhat-release', but of course, this can be applied to any package installed on the filesystem. This is very handy in scripts that need to determine just the version of the package, without the package name and all the sed and grep hackery to get to the data you want. To find out all the support format strings that 'rpm --qf' supports: $ rpm --querytags

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Replace the content of an XML element
Replaces "650" with "999" in simple.xml. xml used - http://www.w3schools.com/xml/simple.xml

Find out current working directory of a process
This is an alternative to another command using two xargs. If it's a command you know there's only one of, you can just use: $ ls -l /proc/$(pgrep COMMAND)/cwd

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

docker kill all containers

Real time duplication of Apache app traffic to a second server
This takes the stream created by apache requests containing jsp and funnels them to another server. I'm using this for simulating real time traffic. The nice command gives ssh maximum CPU cycles, awk & grep strip out everything served by apache. Putting parallel on curl is important because curl is synchronous and waits for the response. Yes, I thought about using wget but it didn't seem any easier. Also, if you figure out how to run this in the background let me know. Every time I background it it stops. If you have multiple front end servers just run multiple instances of this.

Enable programmable bash completion in debian lenny
The really awesome bash completion in debian seems to be an extra package now, which has to be installed. After sourcing /etc/bash_completion it completes almost everything (package names in apt... etc) :-) To make this permanent, put something like this in your .bashrc: if [ -f /etc/bash_completion]; then source /etc/bash_completion fi

Lookup hostname for IP address


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