Commands by ihasn (1)

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print multiplication formulas
seq -s ' ' 1 9 | sed -n ':a;p;s/ *\w$//;h;/^$/t;b a;q' | tac | awk '{for(i=1;i

list block devices
Shows all block devices in a tree with descruptions of what they are.

Calculate pi with specific scale
a() function in bc is for arctangent, available if using -l option included.

ionice limits process I/O, to keep it from swamping the system (Linux)
This command is somewhat similar to 'nice', but constrains I/O usage rather than CPU usage. In particular, the '-c3' flag tells the OS to only allow the process to do I/O when nothing else is pending. This dramatically increases the responsiveness of the rest of the system if the process is doing heavy I/O. There's also a '-p' flag, to set the priority of an already-running process.

a for loop with filling 0 format, with seq
seq allows you to format the output thanks to the -f option. This is very useful if you want to rename your files to the same format in order to be able to easily sort for example: $for i in `seq 1 3 10`; do touch foo$i ;done And $ls foo* | sort -n foo1 foo10 foo4 foo7 But: $for i in `seq -f %02g 1 3 10`; do touch foo$i ;done So $ls foo* | sort -n foo01 foo04 foo07 foo10

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Create an SSH SOCKS proxy server on localhost:8000 that will re-start itself if something breaks the connection temporarily
This command will log you into somehost via SSH and then go into the background (-f). From there, you can point e.g. firefox at localhost:8000 as a SOCKS proxy. Autossh will use port 20000 and 20001 to send and receive test data on those ports to ensure the SSH tunnel is still running, and will try to re-start the tunnel if it goes down. Make sure you have ssh-agent running, or passwordless ssh keys distributed between the two hosts.

Generate binary sequence data

Run bash on top of a vi session (saved or not saved), run multiple commands, instead of one at a time with :!(bashcommand), type exit and [enter] to get back to where you left off in vi.
Helps when I'm editing a script and want to double check some commands without having to exit out of vi multiple times or having to use another terminal session.

Make sure a script is run in a terminal.
Exit with error if script is not run in a terminal

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