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Wrap text files on the command-line for easy reading
fold wraps text at 80 characters wide, and with the -s flag, only causes wrapping to occur between words rather than through them.

Get your external IP address
Request all information about my IP address in json format

password generator
make password randomly, default 8 chars, using bash3.X only, no external program.

Generate a Random MAC address
Use the following variation for FreeBSD: $ openssl rand 6 | xxd -p | sed 's/\(..\)/\1:/g; s/:$//'

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

check open ports without netstat or lsof

find an unused unprivileged TCP port
perl-less way

back ssh from firewalled hosts
host B (you) redirects a modem port (62220) to his local ssh. host A is a remote machine (the ones that issues the ssh cmd). once connected port 5497 is in listening mode on host B. host B just do a ssh 127.0.0.1 -p 5497 -l user and reaches the remote host'ssh. This can be used also for vnc and so on.

cd into another dir to run a one-liner, but implicitly drop back to your $OLD_PWD after
Obviously the example given is necessarily simple, but this command not only saves time on the command line (saves you using "cd -" or, worse, having to type a fully qualified path if your command cd's more than once), but is vital in scripts, where I've found the behaviour of "cd -" to be a little broken at times.

Show bz compressed PF binary log


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