This is my second attempt at writing up my DOS tricks. I changed jobs, just like the original post said, but found the original tricks were woefully inadequate in real world use. Consider this as my first attempt at 'pro' tricks. I'll start with the basics from the command-line.
 
C:\Users\YzOrg>echo %date:~10,4% %date:~4,2%
2010 11

C:\Users\YzOrg>echo hi >  %date:~10,4%%date:~4,2%.txt

C:\Users\YzOrg>dir *.txt
Volume in drive C has no label.
Volume Serial Number is B8EE-D08D

Directory of C:\Users\YzOrg

11/24/2010  09:32 AM                 5 201011.txt
10/01/2010  10:40 AM               210 SDK.txt
               2 File(s)            215 bytes
               0 Dir(s)  199,100,514,304 bytes free

C:\Users\YzOrg>set line=0123456789 ABCD 0123456789 ABCD0123456789 ABCD0123456789 ABCD0123456789

C:\Users\YzOrg>echo %line:~10,8%
ABCD 01

C:\Users\YzOrg>echo hi > demo%date:~10,4%%date:~4,2%%date:~7,2%.log & dir demo*.log
Volume in drive C has no label.
Volume Serial Number is B8EE-D08D

Directory of C:\Users\YzOrg

11/24/2010  09:50 AM                 6 demo20101124.log
               1 File(s)              6 bytes
               0 Dir(s)  199,100,379,136 bytes free

C:\Users\YzOrg>set /?
Displays, sets, or removes cmd.exe environment variables.

SET [variable=[string]]
...<SNIP>

Pitfalls with using %DATE% and %TIME% in filenames

Time and date from OS can have spaces.  So put the log filename in its own variable and use

    SET MYVAR=%MYVAR: =0%

to replace any spaces from %DATE% and %TIME% to 0.

I recommend you follow this guidance, put StdErr redirection at the end of the line.

Here is the final snippet for use in scripts:

Code

set LOG_TIMESTAMP=%date:~10,4%%date:~4,2%%date:~7,2%-%time:~0,2%%time:~3,2%.JobName.log
set LOG_TIMESTAMP=%LOG_TIMESTAMP: =0%
echo starting at %date% %time% with log %CD%\log\%LOG_TIMESTAMP%

Output

starting at Tue 02/13/2011  8:26:57.99 with log C:\Users\YzOrg\log\20110213-0826.JobName.log

Other CMD Tricks

Use %~dp0 to get the full path of the current batch file.  %0 is the scriptname argument, '~dp' are modifiers to get the drive and path of that argument, %~dp0.

Rule: always turn off 'echo' in batch files using this first line:

@if not defined _echo echo off

Use 'set _echo=1' before calling the script to debug it (it will echo every command) References: set /?, call /?, for /?, setlocal /?