X Windows Servers for connectivity from Windows to Linux

XMing (Free)
Exceed Hummingbird
MobaXterm (Free personal and paid professional)
mRemoteNG (Free)
X-Win32 (Paid)

putty

The basic connection program

mputty

Use putty with multiple tabs

puttyCM

putty Connection Manager

Linux bash shell

clear screen – ctrl-l (lowercase L), or clear


Check $HOME/.sh_history.<username> for previous commands


Search through command history on command line: ctrl-r




Linux Memory usage commands




vmstat explained




Truncate a file, or empty/clear contents of a file: cat /dev/null > <filename>