Bash Cheat Sheet

 !! - Last command (usefull if you forget to run a command as sudo)
 sudo !!  (runs last command as sudo)
 !foo - Run most recent command starting with 'foo...' (ex. !ps, !mysqladmin)
 !foo:p - Print command that !foo would run, and add it as the latest to
 command history
 !$ - Last 'word' of last command ('/path/to/file' in the command 'ls -lAFh
 /path/to/file', '-uroot' in 'mysql -uroot')
 !$:p - Print word that !$ would substitute
 !* - All but first word of last command ('-lAFh /path/to/file' in the command
 'ls -lAFh /path/to/file', '-uroot' in 'mysql -uroot')
 !*:p - Print words that !* would substitute

 ^foo^bar - Replace 'foo' in last command with 'bar', print the result, then
 run. ('mysqladmni -uroot', run '^ni^in', results in 'mysqladmin -uroot')

 {a,b,c} passes words to the command, substituting a, b, and c sequentially
 (`cp file{,.bk}` runs `cp file file.bk`)

 Ctrl + a - Jump to the start of the line
 Ctrl + b - Move back a char
 Ctrl + c - Terminate the command
 Ctrl + d - Delete from under the cursor
 Ctrl + e - Jump to the end of the line
 Ctrl + f - Move forward a char
 Ctrl + k - Delete to EOL
 Ctrl + l - Clear the screen
 Ctrl + r - Search the history backwards
 Ctrl + R - Search the history backwards with multi occurrence
 Ctrl + t - Transpose the current char with the previous
 Ctrl + u - Delete backward from cursor
 Ctrl + w - Delete backward a word
 Ctrl + xx - Move between EOL and current cursor position
 Ctrl + x @ - Show possible hostname completions
 Ctrl + z - Suspend/ Stop the command
 Ctrl + x; Ctrl + e - Edit line into your favorite editor

 Alt + < - Move to the first line in the history  Alt + > - Move to the last line in the history
 Alt + ? - Show current completion list
 Alt + * - Insert all possible completions
 Alt + / - Attempt to complete filename
 Alt + . - Yank last argument to previous command
 Alt + b - Move backward
 Alt + c - Capitalize the word
 Alt + d - Delete word
 Alt + f - Move forward
 Alt + l - Make word lowercase
 Alt + n - Search the history forwards non-incremental
 Alt + p - Search the history backwards non-incremental
 Alt + r - Recall command
 Alt + t - Transpose the current word with the previous
 Alt + u - Make word uppercase
 Alt + back-space - Delete backward from cursor

 (Here "2T" means Press TAB twice)
 $ 2T - All available commands(common)
 $ (string)2T - All available commands starting with (string)
 $ /2T - Entire directory structure including Hidden one
 $ (dir)2T - Only Sub Dirs inside (dir) including Hidden one
 $ *2T - Only Sub Dirs inside without Hidden one
 $ ~2T - All Present Users on system from "/etc/passwd"
 $ $2T - All Sys variables
 $ @2T - Entries from "/etc/hosts"
 $ =2T - Output like ls or dir
 .bash_profile = sourced by login shell,
 .bashrc = sourced by all shells,
 .bash_aliases = should be sourced by .bashrc

Run something:
 for i in a b c; do $i 'hello'; done

Do something on a bunch of files:
 for i in *.rb; do echo $i; done

If syntax:
 if [ -e .ssh ]; then echo "hi"; fi

file check flags:
 -e:  file exists
 -f:  regular file (non directory)
 -d:  directory
 -s:  non-zero file
 -x:  execute permission

Avoid duplicates in your history:
 export HISTIGNORE="&:ls:ls *:[bf]g:exit"