Shell expression operators. Need to review frequently.

String Comparison Result
string1 = string2 True if the strings are equal
string1 != string2 True if the strings are not equal
-n string True if the string is not null
-z string True if the string is null (an empty string)
Arithmetic Comparison Result
expression1 -eq expression2 True if the expressions are equal
expression1 -ne expression2 True if the expressions are not equal
expression1 -gt expression2 True if expression1 is greater than expression2
expression1 -ge expression2 True if expression1 is greater than or equal to
expression2
expression1 -lt expression2 True if expression1 is less than expression2
expression1 -le expression2 True if expression1 is less than or equal to
expression2
! expression True if the expression is false, and vice versa
File Conditional Result
-d file True if the file is a directory
-e file True if the file exists. Note that historically the -e option
has not been portable, so -f is usually used.
-f file True if the file is a regular file
-g file True if set-group-id is set on file
-r file True if the file is readable
-s file True if the file has nonzero size
-u file True if set-user-id is set on file
-w file True if the file is writable
-x file True if the file is executable

System Log Rotation Tools

LOGROTATE
logrotate is designed to ease administration of systems that generate
large numbers of log files. It allows automatic rotation, compression,
removal, and mailing of log files. Each log file may be handled daily,
weekly, monthly, or when it grows too large

To disable Apache Info show for security reasons.

I tend to forget the syntax every time, but one of the first things I do when I setup an Apache web server is add/edit these two directive in my httpd.conf:

ServerSignature OffServerTokens Prod

The first one,

ServerSignature Off

tells apache not to display the server version on error pages, or other pages it generates.

The second one

ServerTokens Prod

tells apache to only return Apache in the Server header, returned on every page request.

Why do this?