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Optimal way of deleting huge numbers of files

ssh batch jobs: query hundreds of hosts with an ssh command
Need to query hundreds of hosts with an ssh command ? Of course you'll have setup keys on all your remote HOSTs. But in the case a key is not present this command will skip that node, proceeding on to the next. -t: Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine. Also prevents unwanted stty messages being sent to console -q: Quiet mode. -o "BatchMode yes" If set to yes, passphrase/password querying will be disabled. This option is useful in scripts and other batch jobs where no user is present

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"

add static arp entry to default gateway, arp poison protection

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" }

Google text-to-speech in mp3 format
same but redirecting to player and putting whaever text line.. works on my ubuntu machine ...

List the binaries installed by a Debian package
This shell function displays a list of binaries contained in an installed package; works on Debian based Linux distributions.

Search for a string inside all files in the current directory
options: -n line nbrs, -i ignore case, -s no "doesn't exist", -I ignore binary args: * for all files of current dir (not hidden), .[!.]* for all hidden files I don't include by default the -R (recursive) option, which is not always useful. You add it by hand when needed.

Pulls total current memory usage, including SWAP being used, by all active processes.

Shell function to create a directory named with the current date, in the format YYYYMMDD.
Creates a directory named with the current date, in the format YYYYMMDD. If you give it a directory name as an argument, it will create the new directory inside the specified directory. This is an alternative to command #1993.


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