Commands by andremta (2)

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Copy a file using dc3dd and watch its progress (very nice alternative to dd)
Requires the dc3dd package - available at http://dc3dd.sourceforge.net

command line calculator
simple function , floating point number is supported.

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" }

set your ssd disk as a non-rotating medium
if you still get a permissions error using sudo, then nano the file: sudo nano -w /sys/block/sdb/queue/rotational and change 1 to 0 this thread: http://www.ocztechnologyforum.com/forum/showpost.php?p=369836&postcount=15 says that this will "help the block layer to optimize a few decisions"

To have only unique lines in a file

Insert a line at the top of a text file without sed or awk or bash loops
Yet another way to add a line at the top a of text file with the help of the tac command (reverse cat).

Decreasing the cdrom device speed
Decreasing the cdrom device speed may be more comfortable to watch films (for example)

Renaming a file without overwiting an existing file name
Sometimes in a hurry you may move or copy a file using an already existent file name. If you aliased the cp and mv command with the -i option you are prompted for a confirmation before overwriting but if your aliases aren't there you will loose the target file! The -b option will force the mv command to check if the destination file already exists and if it is already there a backup copy with an ending ~ is created.

Avoids ssh timeouts by sending a keep alive message to the server every 60 seconds
ssh_config is the system-wide configuration file for ssh. For per-user configuration, which allows for different settings for each host: $echo 'ServerAliveInterval 60' >> ~/.ssh/ssh_config On OSX: $echo 'ServerAliveInterval 60' >> ~/.ssh/config or $echo 'ServerAliveInterval 60' >> ~/etc/ssh_config

shows the full path of shell commands

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