Linux 系统基础 - 命令基础概念

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This blog introduce linux command base concept.

Command Format

In linux，your command format look like below :

command [-options] -p

eg : list a directory file

ls -l /directory

Command Edit

Your can edit command in Terminal，you need to know the follwing 2 points :

1. Linux is case sensitive，but window no.
2. Using HM key to move cursor to command head，and END to command tail.

Command Wildcard

Your can use wildcard in command，like below :

# * represents multiple characters.
ls *.c
# ? only represents one characters.
ls ?.c

You can use pipes to import the output of one process as input as another process :

# Search bash process from ps process output.
ps -aux | grep "bash"

You can use input/output redirection :

# Redirection Hello string to 1.txt
echo "Hello" > 1.txt

Command Help

You can use Terminal help tool when you don`t use some command :

man ls
# or
info ls

Note: We often use man *.

Command History

You can use below command to view history command that you have typed :

# Show 12 history cmd.
history 12

Command Alias

You can have an alias for your usual commands :

# Note: = left and right can not leave spaces.
alias my_ls="ls -l"

Background Process

Add & to a command tail let that process run in background :

command &

Exit Shell

Using exit to exit current shell :

exit

Using CTRL-C or q to exit when you inside some documents.

Where is the command ?

When we use command，where is the command ? Type below command in your Terminal :

whereis ls

result:

ls: /bin/ls

This indicates that the order is in /bin/ls. Usually，the command to be stored in there place :

• /bin/
• /sbin/
• /usr/bin/
• /usr/sbin/

You can use ls /bin/ to show those command.