zdump -v /etc/localtime|grep 2008

/etc/localtime  Sun Mar  9 06:59:59 2008 UTC =
    Sun Mar 9 01:59:59 2008 EST isdst=0 gmtoff=-18000
/etc/localtime  Sun Mar  9 07:00:00 2008 UTC =
    Sun Mar 9 03:00:00 2008 EDT isdst=1 gmtoff=-14400
/etc/localtime  Sun Nov  2 05:59:59 2008 UTC =
    Sun Nov 2 01:59:59 2008 EDT isdst=1 gmtoff=-14400
/etc/localtime  Sun Nov  2 06:00:00 2008 UTC =
    Sun Nov 2 01:00:00 2008 EST isdst=0 gmtoff=-18000

Obviously, change 2008 to whatever year you want.

ps -eo pcpu,pid,user,args | sort -k1 -r | head -11

Substitue pcpu above with pmem to see the memory hogs instead.

#!/bin/sh

log_message() {
    echo `date "+%m/%d/%y %H:%M:%S %Z"` "$1" | tee -a aaa.out
}

log_message "Hello there"
log_message "Goodbye"

Sample output:

08/28/07 23:16:13 EDT Hello there
08/28/07 23:16:13 EDT Goodbye

http://www.macosxhints.com/article.php?story=20060602180942480

curl --silent http://checkip.dyndns.org
    | awk '{print $6}' | cut -f 1 -d "<"

If you are using Apple's Airport Extreme Basestation (mine is particularly the Time Capsule and this is where I have tested this), and you have the SNMP interface enabled, you can run the following command

prompt$ snmpwalk -Os -c public -v 1 192.168.63.1 ipAdEntAddr IpAddress \
    | grep -E -v '(127.0.0|169.254|192.168.63.1)' \
    | cut -d : -f 2 | sed 's/ //g'

To convert a text file with DOS line termination to UNIX line termination:

tr -d '\015' < winfile.txt > unixfile.txt

or

sed s/.$// winfile.txt > unixfile.txt

To convert a unix file to a DOS file:

sed s/$/\x0d/ unixfile.txt > winfile.txt

#!/bin/sh

if [ `id -u` != 0 ]; then
  echo "Permission denied, must be root"
  exit
fi

# Do the thing...

#!/usr/bin/env perl

print "Username: ";
chomp($uname = <stdin>);

$pwd = (getpwnam($uname))[1]; # get the user's pwd
die "invalid user\n" unless defined $pwd and length $pwd;
$salt = substr($pwd, 0, 2);

system "stty -echo";
print "Password: ";
chomp($word = <stdin>);
print "\n";
system "stty echo";

if (crypt($word, $salt) ne $pwd) {
    die "Sorry...\n";
} else {
    print "ok\n";
}

——————————————————

Creating a data CD:

Step 1: Make a directory to contain the files you want to place on the the CD. “mkdir /image/userdir/” is the standard method.

Step 2: Copy the files from wherever they are to the directory you just created.

Step 3: Create the ISO9660 image that will be burned on the CD. You do this using the mkisofs command. An example command is:

csh> cd /image/userdir/
csh> mkisofs -o /image/burn-image/.iso
-l -R -L -V "" -P "" -p "" -A "" .

-o: the name of the file that will contain the
     image
-l: use long file names
-R: use Rock Ridge extensions. This means
     that long filenames will be used, file
     uid/gids and permissions will be preserved,
     symbolic links will be included, etc. In
     other words, the CD will try hard to
     emulate a Unix file system.
[-r: This is like the -R option, but file uid/gid
are set to 0, files will be readable by anyone
and all write permissions will be removed.
Use this switch if you anticipate needing to
read the CD in an environment where your
uid/gid do not exist. E.g., if you are sending
to CD to another institution.]

-L: Allow file names beginning with '.'.
-V, -P, -p, -A: See the mkisofs man page.

The final argument (in the example '.') is the
name of the top-level directory containing
file data.

See the mkisofs manual page for further details.

Mkisofs is fairly chatty about what it is doing, so you will know that progress is being made.

Step 4: Burn the just-created ISO9660 image onto the CD. First place a CD in drive (duh!). Then issue the command:

csh> cdrecord -v speed=8 -pad -data \
        /image/burn-image/.iso

The drive is capable of handling re-writable media. However, re-writing is slower than writing for the first time and cdrecord may downgrade your request for speed=8 to something lower. If your CD has been written before you may also need to ‘blank’ it as well. In this case, the command line will be:

csh> cdrecord -blank=fast -v speed=8 -pad \
     -data /image/burn-image/.iso

Step 5: CLEAN UP AFTER YOURSELF. There is a limited amount of disk space available for data and images. Don’t leave your gunk laying around where someone will trip over it:

csh> rm -r /image/userdir/
csh> rm /image/burn-image/.iso

——————————————————

Creating audio CDs:

Step 1: Make a directory to contain the files you want to place on the the CD. “mkdir /image/userdir/” is the standard method.

Step 2: Copy the files from wherever they are to the directory you just created. This example assumes that the audio is formatted as .WAV files; other formats can be used with a little extra work, see the cdrecord man page for details.

Step 3: Place a CD in drive (duh!). Then issue the command:

csh> cdrecord -v speed=8 -pad \
         -audio /image/userdir/*.wav

The drive is capable of handling re-writable media. However, re-writing is slower than writing for the first time. So if you are re-writing a CD, use “speed=4″.

Step 4: CLEAN UP AFTER YOURSELF. There is a limited amount of disk space available for data and images. Don’t leave your gunk laying around where someone will trip over it:

csh> rm -r /image/userdir/

image = /vmlinuz
        label = Linux
        root = /dev/hda1
        password = wingedlizard
        restricted
        read-only

Then chmod this file 600 (so nobody but root can read it) and re-run /sbin/lilo.

The “restricted” keyword means that LILO will stop and ask for a password if you try to boot this kernel with _any_ keywords such as “1″ or “single” or “init=/bin/bash”. A password won’t be required during normal (no-added-keywords) boots.

du -sk * | sort -rn