-Qdt Lists dependencies/packages which are no longer required by any packages -q Output only package name (not the version number) -R Remove package(s) Rest is self-explanatory. I just started out with Arch - so if there is any better/standard method to achieve the same - please suggest.
This will parse a random command json entry from http://commandlinefu.com A must have in your .bash_profile to learn new shell goodies at login!!!
it is generally advised to avoid using which(1) whenever possible. which(1) is usually a csh(1) script, or sometimes a compiled binary. It's output is highly variable from operating system to operating system, so platform independent scripts could become quite complicated with the logic. On HP-UX 10.20, for example, it prints "no bash in /path /path /path ..."; on OpenBSD 4.1, it prints "bash: Command not found."; on Debian (3.1 through 5.0 at least) and SuSE, it prints nothing at all; on Red Hat 5.2, it prints "which: no bash in (/path:/path:...)"; on Red Hat 6.2, it writes the same message, but on standard error instead of standard output; and on Gentoo, it writes something on stderr. And given all these differences, it's still variable based on your shell. This is why POSIX is king. See http://mywiki.wooledge.org/BashFAQ/081 for more ways on avoiding which(1). Show Sample Output
sleep 1h ; sudo command
or
sudo sleep 1h ; sudo command
won't work, because by the time the delay is up, sudo will want your password again.
Obviously the example given is necessarily simple, but this command not only saves time on the command line (saves you using "cd -" or, worse, having to type a fully qualified path if your command cd's more than once), but is vital in scripts, where I've found the behaviour of "cd -" to be a little broken at times. Show Sample Output
This one-liner will output installed packages sorted by size in Kilobytes. Show Sample Output
Sometimes you don't have man pages only '-h' or '--help'.
Can be integrated into your .bashrc if you like. You'll probably want to grep out my name. Show Sample Output
you could save the code between if and fi to a shell script named smiley.sh with the first argument as and then do a smiley.sh to see if the command succeeded. a bit needless but who cares ;) Show Sample Output
[ 2000 -ge "$(free -m | awk '/buffers.cache:/ {print $4}')" ] returns true if less than 2000 MB of RAM are available, so adjust this number to your needs. [ $(echo "$(uptime | awk '{print $10}' | sed -e 's/,$//' -e 's/,/./') >= $(grep -c ^processor /proc/cpuinfo)" | bc) -eq 1 ] returns true if the current machine load is at least equal to the number of CPUs. If either of the tests returns true we wait 10 seconds and check again. If both tests return false, i.e. 2GB are available and machine load falls below number of CPUs, we start our command and save it's output in a text file. The ( ( ... ) & ) construct lets the command run in background even if we log out. See http://www.commandlinefu.com/commands/view/3115/ .
I like much more the perl solution, but without using perl. It launches a backgroup process that will kill the command if it lasts too much. A bigger function: check_with_timeout() { [ "$DEBUG" ] && set -x COMMAND=$1 TIMEOUT=$2 RET=0 # Launch command in backgroup [ ! "$DEBUG" ] && exec 6>&2 # Link file descriptor #6 with stderr. [ ! "$DEBUG" ] && exec 2> /dev/null # Send stderr to null (avoid the Terminated messages) $COMMAND 2>&1 >/dev/null & COMMAND_PID=$! [ "$DEBUG" ] && echo "Background command pid $COMMAND_PID, parent pid $$" # Timer that will kill the command if timesout sleep $TIMEOUT && ps -p $COMMAND_PID -o pid,ppid |grep $$ | awk '{print $1}' | xargs kill & KILLER_PID=$! [ "$DEBUG" ] && echo "Killer command pid $KILLER_PID, parent pid $$" wait $COMMAND_PID RET=$? # Kill the killer timer [ "$DEBUG" ] && ps -e -o pid,ppid |grep $KILLER_PID | awk '{print $1}' | xargs echo "Killing processes: " ps -e -o pid,ppid |grep -v PID | grep $KILLER_PID | awk '{print $1}' | xargs kill wait sleep 1 [ ! "$DEBUG" ] && exec 2>&6 6>&- # Restore stderr and close file descriptor #6. return $RET }
You can record, then replay a series of keystrokes in vim. In command mode 'q', then a letter [a-zA-Z] starts macro recording mode. Enter a series of vim commands. When done, enter command mode again, and press 'q' to stop recording. To replay, enter command mode, then press @{letter}
Tested on debian and ubuntu. Translations could be useless, so "LANG=C man intro" is a better alternative.
An easy function to get a process tree listing (very detailed) for all the processes of any gived user. This function is also in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html Show Sample Output
dsh - Distributed shell, or dancer?s shell ;-) you can put your servers into /etc/dsh/machines.list than you don't have to serperate them by commata or group them in different files and only run commands for this groups dsh -M -c -a -- "apt-get update" Show Sample Output
In Bash, when defining an alias, one usually loses the completion related to the function used in that alias (that completion is usually defined in /etc/bash_completion using the complete builtin). It's easy to reuse the work done for that completion in order to have smart completion for our alias. That's what is done by this command line (that's only an example but it may be very easy to reuse). Note 1 : You can use given command line in a loop "for old in apt-get apt-cache" if you want to define aliases like that for many commands. Note 2 : You can put the output of the command directly in your .bashrc file (after the ". /etc/bash_completion") to always have the alias and its completion Show Sample Output
tired of switching to the console to check if some command has finished yet? if notify-send does not work on your box try this one... e.g. rsync -av -e /usr/bin/lsh $HOME slowconnection.bar:/mnt/backup ; z (now fire up X, do something useful, get notified if this stuff has finished).
Obviously, you can replace 'man' command with any command in this command line to do useful things. I just want to mention that there is a way to list all the commands which you can execute directly without giving fullpath. Normally all important commands will be placed in your PATH directories. This commandline uses that variable to get commands. Works in Ubuntu, will work in all 'manpage' configured *nix systems. Show Sample Output
man -t manpagename gives a postscript version of said man page. You then pipe it to ls, and assuming you have cups set up, it prints in your default printer. Show Sample Output
The ssh command alone will execute the sudo command remotely, but the password will be visible in the terminal as you type it. The two stty commands disable the terminal from echoing the password back to you, which makes the remote sudo act as it does locally.
Want to know why your load average is so high? Run this command to see what processes are on the run queue. Runnable processes have a status of "R", and commands waiting on I/O have a status of "D". On some older versions of Linux may require -emo instead of -eo. On Solaris: ps -aefL -o s -o user -o comm | egrep "^O|^R|COMMAND" Show Sample Output
Simply pass an argument to the script to convert the manual page to a PDF:
man2pdf drutil
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