Check These Out
This version uses Pipes, but is easier for the common user to grasp... instead of using sed or some other more complicated method, it uses the tr command
Someone might attack on your system. You can drop attacker IP using IPtables. However, you can use route command to null route unwanted traffic. A null route (also called as blackhole route) is a network route or kernel routing table entry that goes nowhere. Matching packets are dropped (ignored) rather than forwarded, acting as a kind of very limited firewall. The act of using null routes is often called blackhole filtering.
Doesn't work so well if you connect from windows. Linux only sends LF where windows wants CRLF. The alternative command works better with windows, however it uses script and a named pipe.
Convert all jpegs in the current directory into ~1024*768 pixels and ~ 150 KBytes jpegs
no need to reinvent the wheel.
Thanks to the OP for the "obsolete" hint. 'declare' may come in pretty handy on systems paranoid about "up-to-dateness"
Replace * with any filename matching glob or an individual filename
When trying to play a sound you may sometimes get an error saying that your sound card is already used, but not by what process. This will list all processes playing sound, useful to kill processes that you no longer need but that keep using your sound card.
Uses the lm-sensors package in Linux to display fan speed. Grep RPM is used to discover lines containing the text RPM, and sed is used to edit out everything but the RPM number. The watch utility is used to update the display every 10 seconds and -d highlights any changes from the previous value. The eval function of Bash is used to execute the command enclosed in the ".." string.
This is different that `who` in that who only cares about logged-in users running shells, this command will show all daemon users and what not; also users logged in remotely via SSH but are running SFTP/SCP only and not a shell.