Commands by oauy3fbx (0)

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Get information about libraries currently installed on a system.
This command is very helpful when we need to duplicate a test scenario and first we want to find out the installed libraries together with the version and release numbers and architecture. (look example) Command can be tuned by choosing just the names of libraries we are interested in. For example glibc and gcc.

Record microphone input and output to date stamped mp3 file
record audio notes or meetings requires arecord and lame run mp3gain on the resulting file to increase the volume / quality ctrl-c to stop recording

prints line numbers
the sed way to print line numbers

Have netcat listening on your ports and use telnet to test connection
This will start a netcat process listening on port 666. If you are able connect to your your server, netcat will receive the data being sent and spit it out to the screen (it may look like random garbage, so you might want to redirect it to a file).

Find and display most recent files using find and perl
This pipeline will find, sort and display all files based on mtime. This could be done with find | xargs, but the find | xargs pipeline will not produce correct results if the results of find are greater than xargs command line buffer. If the xargs buffer fills, xargs processes the find results in more than one batch which is not compatible with sorting. Note the "-print0" on find and "-0" switch for perl. This is the equivalent of using xargs. Don't you love perl? Note that this pipeline can be easily modified to any data produced by perl's stat operator. eg, you could sort on size, hard links, creation time, etc. Look at stat and just change the '9' to what you want. Changing the '9' to a '7' for example will sort by file size. A '3' sorts by number of links.... Use head and tail at the end of the pipeline to get oldest files or most recent. Use awk or perl -wnla for further processing. Since there is a tab between the two fields, it is very easy to process.

floating point operations in shell scripts
allows you to use floating point operations in shell scripts

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Terrorist threat level text

Adding formatting to an xml document for easier reading
This will indent the input to be more readable. Warnings and messages are not send to STDOUT so you can just use a pipe to create the formatted outputfile, like: $ tidy -i -xml in.xml > out.xml

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" }

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