All commands

AIX user administration whithout smitty

There is a limit to how many processes you can run at the same time for each user, especially with web hosts. If the maximum # of processes for your user is 200, then the following sets OPTIMUM_P to 100.

This is very useful in scripts because this is such a fast low-resource-intensive (compared to ps, who, lsof, etc) way to determine how many processes are currently running for whichever user. The number of currently running processes is subtracted from the high limit setup for the account (see limits.conf, pam, initscript).

An easy to understand example- this searches the current directory for shell scripts, and runs up to 100 'file' commands at the same time, greatly speeding up the command.

I am using it in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html especially for the xargs command. Xargs has a -P option that lets you specify how many processes to run at the same time. For instance if you have 1000 urls in a text file and wanted to download all of them fast with curl, you could download 100 at a time (check ps output on a separate [pt]ty for proof) like this:

I like to do things as fast as possible on my servers. I have several types of servers and hosting environments, some with very restrictive jail shells with 20processes limit, some with 200, some with 8000, so for the jailed shells my xargs -P10 would kill my shell or dump core. Using the above I can set the -P value dynamically, so xargs always works, like this.

If you were building a process-killer (very common for cheap hosting) this would also be handy.

Note that if you are only allowed 20 or so processes, you should just use -P1 with xargs.

It is helpful to know the current limits placed on your account, and using this shortcut is a quick way to figuring out which values to change for optimization or security. Here's the result of this command:

core file size (blocks, -c) 0

data seg size (kbytes, -d) unlimited

scheduling priority (-e) 0

file size (blocks, -f) unlimited

pending signals (-i) 155648

max locked memory (kbytes, -l) 32

max memory size (kbytes, -m) unlimited

open files (-n) 8192

pipe size (512 bytes, -p) 8

POSIX message queues (bytes, -q) 819200

real-time priority (-r) 0

stack size (kbytes, -s) 10240

cpu time (seconds, -t) unlimited

max user processes (-u) unlimited

virtual memory (kbytes, -v) unlimited

file locks (-x) unlimited

traverses e.g. "/data/myhost1.com/myrsyncshare"; logs stderr and stdout. useful with cron.

Find C/C++ source files and headers in the current directory.

This makes an alias for a command named 'busy'. The 'busy' command opens a random file in /usr/include to a random line with vim. Drop this in your .bash_aliases and make sure that file is initialized in your .bashrc.

Purely frivolous - print a sine/cosine curve to the console - the width varies as it progresses. Ctrl-C to halt.

Use Ruby's standard Curses module to display a Lissajous curve in the console. Replace the "0.2" with different numbers for different curves.

for exemple :

this will display "hello" with bash

with zsh, by default, this will make an error :

"command not found : echo hello"

hwordsplit option permit zsh to act like bash on this point

make sure that flac and lame are installed

sudo apt-get install lame flac

The above command will open a Remote Desktop connection from command line, authenticate using default username and password (great for virtual machines; in the exampe above it's administrator:password), create a shared folder between your machine and the other machine and configure resolution to best fit your desktop (I don't like full screen because it make the desktop panels to disappear). The command will run in the background, and expect to receive parameters. You should enter hostname or IP address as a parameter to the command, and can also override the defaults parameters with your own.

Dumps a compressed svn backup to a file, and emails the files along with any messages as the body of the email

Usage:

Example:

Usage:

Example:

Better use iproute2 !

It grabs all the database names granted for the $MYSQLUSER and gzip them to a remote host via SSH.

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.

same thing without loop ;)

See http://code.google.com/apis/analytics/docs/concepts/gaConceptsCookies.html if you are unclear about the Google Analytics cookie system. If Firefox is your daily browser, be a good Orwellian and run this command regularly.

If you see, 'SQL error near line 1: database is locked', close Firefox and run again.