Web-based Scripts (i.e. those that will run in a browser window): Upper-case first letter, then upper-case letter for the start of each word after that. Should have a '.cgi' suffix. Choose a name that indicates what the script does:

DeviceNamer.cgi
VlanFinder.cgi
TagGenerator.cgi

Command-line scripts: All lower-case letters. Underscores between words. Should have a suffix that makes sense (e.g. '.pl' if it's written in Perl, '.py' if written in Python, '.sh' if a shell script). Choose a name that indicates what the script does:

platform_vlan_audit.pl
macwatch_monitor.pl
wiscnic_text_input.pl

Subroutines and Functions: Lower-case first letter, then upper-case letter for the start of each word after that. Choose something that indicates clearly what the function does.

createNewUserRecord()
getDeviceNameFromURL()
sortByIPAddress()

Variables: All lower-case. Underscores between words. Choose something descriptive and avoid abbreviation unless it's clear what is meant:

$my_variable_name
$stp_root_value
$dhcp_department_descr

NOTE: Dale uses an upper-case first letter to indicate a global-scope variable.

Constants and file-handles: All upper-case letters. Underscores between words:

$PI
$DAYS_IN_MONTH
$MAX_RECORDS
$TXT_INPUT_FILE
open (LOG, "$logfile");

Hashes and Arrays: Same convention as other variables, but do NOT use the word "array" or "hash" in the name:

my %device_info = ();
my %ip_addresses = ();
my @user_net_ids = ();

NOT

my %device_info_hash = ();
my %ip_address_hash = ();
my @user_net_id_array = ();