Commands tagged command

Requires mencoder.

Execute a process or list of commands in the given interval and output the difference in output.

Using the output of 'ps' to determine CPU usage is misleading, as the CPU column in 'ps' shows CPU usage per process over the entire lifetime of the process. In order to get *current* CPU usage (without scraping a top screen) you need to pull some numbers from /proc/stat. Here, we take two readings, once second apart, determine how much IDLE time was spent across all CPUs, divide by the number of CPUs, and then subtract from 100 to get non-idle time.

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).

eg:

Already running cmd

Substitution cmd

5 helpful aliases for using the which utility, specifically for the GNU which (2.16 tested) that is included in coreutils.

Which is run first for a command. Same as type builtin minus verbosity

Which (a)lias

Which (f)unction

Which e(x)ecutable file in PATH

Which (all) alias, function, builtin, and files in PATH

# From my .bash_profile http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

Normally the bash builtin command 'set' displays all vars and functions. This just shows the vars. Useful if you want to see different output then env or declare or export.

Alias 'sete' shows sets variables

Alias setf shows the functions.

Also see: http://www.commandlinefu.com/commands/view/6899/print-all-environment-variables-including-hidden-ones

At the very least, some cool sed commands!

From my .bash_profile http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

While going through the source code for the well known ps command, I read about some interesting things.. Namely, that there are a bunch of different fields that ps can try and enumerate for you. These are fields I was not able to find in the man pages, documentation, only in the source.

Here is a longer function that goes through each of the formats recognized by the ps on your machine, executes it, and then prompts you whether you would like to add it or not. Adding it simply adds it to an array that is then printed when you ctrl-c or at the end of the function run. This lets you save your favorite ones and then see the command to put in your .bash_profile like mine at : http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

Note that I had to do the exec method below in order to pause with read.

t ()

{

local r l a P f=/tmp/ps c='command ps wwo pid:6,user:8,vsize:8,comm:20' IFS=' ';

trap 'exec 66

exec 66 $f && command ps L | tr -s ' ' >&$f;

while read -u66 l >&/dev/null; do

a=${l/% */};

$c,$a k -${a//%/} -A;

yn "Add $a" && P[$SECONDS]=$a;

done

}

This will show you any links that a command follows (unlike 'file -L'), as well as the ultimate binary or script.

Put the name of the command at the very end; this will be passed to perl as the first argument.

For obvious reasons, this doesn't work with aliases or functions.

* Add comment with # in your command

* Later you can search that command on that comment with CTRL+R

In the title command, you could search it later by invoking the command search tool by first typing CTRL+R and then typing "revert"

This little function will smarten 'cd'. If you try to cd into a file (which I guess we all have done), it cd's into the directory of that file instead.

I had to use nesten if's, to get cd to still work with 'cd' (to get to $HOME), 'cd -' (to get to last directory), and 'cd foo\ bar'.