Shell command interpreter, user and kernel interaction
bash
the Tab key to complete the command or file name
up and down keys to find the command history
clear = ctrl + l clear screen
ctrl + u Delete the character of the command line
Command aliases
Easy to remember
command name: alias
Function Description: Defines the alias
syntax: alias cp = Copy
Alias RM = "RM -rf"
unalias Copy delete an alias
Input / output redirection
Non-standard input and output
Shell process for each of three pre-defined file descriptors
0 standard input display
a standard keyboard output
2 stderr
output redirection
ls / tmp> /tmp.msg
emptied original document, the output to a file
ls / tmp >> /tmp.msg
results appended to the file
input redirection
wall </ etc / text
file text broadcasted
error output
command 2> error file
ls / tmp 2> ls.err
pipeline
The output of a command input to transmit another command, another command as
ls -l / etc | more
Command connector
; Command interval sequentially performed
&& Logical previously performed only after a successful execution, a failed after the first does not perform
|| logical OR, the first command execution fails before the second, the first successful second one does not perform
Alternatively command character
The output of a command as a parameter of another command
ls -l which touchoutput as a parameter which touch the ls -l