linux command
ls / show root directory
touch . . . create. . .
ls -a show hidden ls -l list show ls -h show file size
query command --help help information man query help
tab autocompletion
gedit filename Edit this file
cat file name Query file content
history history command
! number The command to execute this number
rm file delete file
wildcard *? 【】
ls 2* displays files starting with 2
ls 2? Display 2 digit files starting with 2? represent only one
ls 2 [12345 or 1-5] range
redirect
ls >> content append
