Commands by ztank1013 (9)

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Change Title of Terminal Window to Verbose Info useful at Login
I usually have 5 or more ssh connections to various servers, and putting this command in my .bash_profile file makes my putty window or x terminal window title change to this easily recognizable and descriptive text. Includes the username, group, server hostname, where I am connecting from (for SSH tunneling), which device pts, current server load, and how many processes are running. You can also use this for your PROMPT_COMMAND variable, which updates the window title to the current values each time you exec a command. I prefix running this in my .bash_profile with $ [[ ! -z "$SSH_TTY" ]] && which makes sure it only does this when connecting via SSH with a TTY. Here's some rougher examples from http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html $ # If set, the value is executed as a command prior to issuing each primary prompt. $ #H=$((hostname || uname -n) 2>/dev/null | sed 1q);W=$(whoami) $ #export PROMPT_COMMAND='echo -ne "\033]0;${W}@${H}:${PWD/#$HOME/~} ${SSH_TTY/\/dev\//} [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"`]\007"' $ #PROMPT_COMMAND='echo -ne "\033]0;`id -un`:`id -gn`@`hostname||uname -n 2>/dev/null|sed 1q` `command who -m|sed -e "s%^.* \(pts/[0-9]*\).*(\(.*\))%[\1] (\2)%g"` [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"` / `command ps aux|wc -l`]\007"' $ #[[ -z "$SSH_TTY" ]] || export PROMPT_COMMAND $ #[[ -z "$SSH_TTY" ]] && [[ -f /dev/stdout ]] && SSH_TTY=/dev/stdout And here's a simple function example for setting the title: $ function set_window_title(){ echo -e "\033]0; ${1:-$USER@$HOST - $SHLVL} \007"; }

power off system in X minutes
Replace 60 with the number of minutes until you want the machine to shut down. Alternatively give an absolute time in the format hh:mm (shutdown -h 9:30) Or shutdown right away (shutdown -h now)

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" }

Which files/dirs waste my disk space
I added -S to du so that you don't include /foo/bar/baz.iso in /foo, and change sorts -n to -h so that it can properly sort the human readable sizes.

Simple addicting bash game.
Really bored during class so I made this... Basically, you hold period (or whatever) and hit enter after a second and you need to make the next line of periods the same length as the previous line... My record was 5 lines of the same length. It's best if you do it one handed with your pointer on period and ring on enter.

run command on a group of nodes in parallel
The pee command is in the moreutils package.

Show Apt/Dpkg configuration
Shows all configurations to apt and dpkg, rarely changed, you probably still have the default configuration. Go ahead and explore your configuration if you dare, perhaps change your apt-cache directory, Dir::Cache "var/cache/apt/"; or the names of the log files.

Recursively remove directory with many files quickly
rsync'ing an empty directory over a directory to be deleted recursively is much faster than using rm -rf, for various reasons. Relevant only for directories with really a lot of files.

vim read stdin

all out
How to force a userid to log out of a Linux host, by killing all processes owned by the user, including login shells:


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