Commands by mechmind (7)

  • It's useful mostly for your custom scripts, which running on specific host and tired on ssh'ing every time when you need one simple command (i use it for update remote apt repository, when new package have to be downloaded from another host). Don't forget to set up authorization by keys, for maximum comfort. Show Sample Output

    echo -e '#!/bin/bash\nssh remote-user@remote-host $0 "$@"' >> /usr/local/bin/ssh-rpc; chmod +x /usr/local/bin/ssh-rpc; ln -s hostname /usr/local/bin/ssh-rpc; hostname
    mechmind · 2011-12-28 17:43:34 5
  • There are a lot of commands, which invokes your player at specified time. But I prefer not to jump from by bed, when alarm start to play. Instead, this script increases volume of mpd over time, which much more pleasant when you just woke up :)

    at 8:30 <<<'mpc volume 20; mpc play; for i in `seq 1 16`; do sleep 2; mpc volume +5; done'
    mechmind · 2011-11-30 17:51:27 1
  • this oneliner uses make and it's jobserver for parallel execution of your script. The '-j' flag for make defines number of subprocesses to launch, '-f' tells make use stdin instead of Makefile. Also make have neat flag '-l', which "Specifies that no new jobs (commands) should be started if there are others jobs running and the load is at least load (a floating-point number)." Also you can use plain Makefile, for better readability: targets = $(subst .png,.jpg,$(wildcard *.png)) (targets): echo convert $(subst .jpg,.png,$@) $@ all : $(targets)

    echo -n 'targets = $(subst .png,.jpg,$(wildcard *.png))\n$(targets):\n convert $(subst .jpg,.png,$@) $@ \nall : $(targets)' | make -j 4 -f - all
    mechmind · 2010-07-15 07:19:17 1
  • USAGE: $ sudor your command This command uses a dirty hack with history, so be sure you not turned it off. WARNING! This command behavior differ from other commands. It more like text macro, so you shouldn't use it in subshells, non-interactive sessions, other functions/aliases and so on. You shouldn't pipe into sudor (any string that prefixes sudor will be removed), but if you really want, use this commands: proceed_sudo () { sudor_command="`HISTTIMEFORMAT=\"\" history 1 | sed -r -e 's/^.*?sudor//' -e 's/\"/\\\"/g'`" ; pre_sudor_command="`history 1 | cut -d ' ' -f 5- | sed -r -e 's/sudor.*$//' -e 's/\"/\\\"/g'`"; if [ -n "${pre_sudor_command/ */}" ] ; then eval "${pre_sudor_command%| *}" | sudo sh -c "$sudor_command"; else sudo sh -c "$sudor_command" ;fi ;}; alias sudor="proceed_sudo # "

    proceed_sudo () { sudor_command="`HISTTIMEFORMAT=\"\" history 1 | sed -r -e 's/^.*?sudor//' -e 's/\"/\\\"/g'`" ; sudo sh -c "$sudor_command"; }; alias sudor="proceed_sudo # "
    mechmind · 2010-06-29 14:56:29 0
  • For this hack you need following function: finit() { count=$#; current=1; for i in "$@" ; do echo $current $count; echo $i; current=$((current + 1)); done; } and alias: alias fnext='read cur total && echo -n "[$cur/$total] " && read' Inspired by CMake progress counters. Show Sample Output

    finit "1 2 3" 3 2 1 | while fnext i ; do echo $i; done;
    mechmind · 2010-06-17 10:20:49 0
  • When you start screen as `ssh-agent screen`, agent will die after detatch. If you don't want to take care about files when stored agent's pid/socket/etc, you have to use this command.

    eval `ssh-agent`; screen
    mechmind · 2010-03-07 14:58:54 0
  • With this form you dont need to cut out target directory using grep/sed/etc.

    (ls; mkdir subdir; echo subdir) | xargs mv
    mechmind · 2009-11-08 11:40:55 5

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Cleanup a (source) text file, removing trailing spaces/tabs and multiple consecutive blank lines
I used this command (in addition to a code formatting tool) to "cleanup" a bunch of PHP files

list files recursively by size

Hostname tab-completion for ssh
This is meant for the bash shell. Put this function in your .profile and you'll be able to use tab-completion for sshing any host which is in your known_hosts file. This assumes that your known_hosts file is located at ~/.ssh/known_hosts. The "complete" command should go on a separate line as such: function autoCompleteHostname() { local hosts=($(awk '{print $1}' ~/.ssh/known_hosts | cut -d, -f1)); local cur=${COMP_WORDS[COMP_CWORD]}; COMPREPLY=($(compgen -W '${hosts[@]}' -- $cur )) } complete -F autoCompleteHostname ssh

Prevent non-root users from logging in
Also with optional message: $ echo "no login for you" > /etc/nologin (This doesn't affect your current X session - you're already logged in!)

positions the mysql slave at a specific master position
say you want to reinitialize the slave database without resetting the master positions. You stop the slave, dump the master database with --master-data=2 then execute the command on the slave and wait for it to stop at the exact position of the dump. reinit the slave db and start the slave. enjoy.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Copy the text from the 3rd line to the 9th line into a new file with VI

Grab the first 3 octets of your ip addresses
For machines that have many ip blocks spanning different Class C's, this will show which ones.

Updated top ten memory utilizing processes (child/instance aggregation) now with percentages of total RAM
Prints the top 10 memory consuming processes (with children and instances aggregated) sorted by total RSS and calculates the percentage of total RAM each uses. Please note that since RSS can include shared libraries it is possible for the percentages to add up to more that the total amount of RAM, but this still gives you a pretty good idea. Also note that this does not work with the mawk version of awk, but it works fine with GNU Awk which is on most Linux systems. It also does not work on OS X.

RTFM function
Simple edit to work for OSX. Now just add this to your ~/.profile and `source ~/.profile`

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