Use your Linux keyboard

Use your Linux keyboard-general Linux technology-Linux programming and kernel information. For more information, see the following. Correct use of the symbols on the keyboard can help you fully apply various techniques when writing simple scripts.

[Tab] is used to automatically complete a command, path, or file name.

[Root @ localhost ~] # After Entering the user, the user can connect to the [Tab] key on the keyboard to list commands starting with the user.

[Root @ localhost ~] # After Entering usera, usera can press the [Tab] key on the keyboard to automatically complete the useradd command starting with usera.

[Root @ localhost ~] # After useradd is input, you can press the [Tab] key twice on the keyboard to list all files and directories in the current directory.

~ This symbol represents the user's home directory.

[Root @ localhost ~] # Cd/

[Root @ localhost ~] # Pwd

[Root @ localhost ~] # Cd ~

[Root @ localhost ~] # Pwd

! Add this symbol before a command to call the previous command starting with this command in the command history [root @ localhost ~] # Find/root/install. log

[Root @ localhost ~] # File/root/install. log

[Root @ localhost ~] #! F The command will call file/root/install to find the file.

[Root @ localhost ~] #! Fi will call the file/root/install command to find the file.

[Root @ localhost ~] #! Fin will call the find/root/install command to find the file.

$ Is used to reference a variable.

[Root @ localhost ~] # Myhost = www.liuziyang.cn

[Root @ localhost ~] # Echo $ myhost

& At the end of a command, the task is run in the background

% Indicates the number of a task (the task is not a process ).

[Root @ localhost ~] # While true; do echo hello>/dev/tty2; sleep 1; done &

[Root @ localhost ~] # While true; do echo www.liuziyang.cn>/dev/tty2; sleep 1; done &

[Root @ localhost ~] # [Ctrl] + [alt] + [F2] here it means to switch to the second console/dev/tty2 and view the output result

After each execution of the following command, switch between [ctrl] + [alt] + [F1] and [F2] To see a result change.

[Root @ localhost ~] # Jobs

[Root @ localhost ~] # Fg % 1

[Root @ localhost ~] # [Ctrl] + z the combination of [ctrl] and z on the keyboard

[Root @ localhost ~] # Jobs [root @ localhost ~] # Kill % 2

[Root @ localhost ~] # Jobs

[Root @ localhost ~] # Bg % 1

[Root @ localhost ~] # Jobs

[Root @ localhost ~] # Kill % 1 ''represents a command or script'' represents a string "" represents a string

Check the output result of each command.

[Root @ localhost ~] # Echo 'hostname'

[Root @ localhost ~] # Echo 'hostname'

[Root @ localhost ~] # Echo "hostname" | pipeline symbol used for filtering after a command statement

[Root @ localhost ~] # Ls-l/etc | more

[Root @ localhost ~] # Cat/etc/passwd | awk-F: '{print $7}' | sort | uniq

^ Match the start of a string

$ Match the end of a string

> Targeted symbols

<Targeted symbol

> Append symbol

Note that the output results of each command are compared.

[Root @ localhost ~] # Grep ^ root </etc/passwd> result1.txt

[Root @ localhost ~] # Cat result1.txt

[Root @ localhost ~] # Grep bash $ </etc/passwd> result1.txt

[Root @ localhost ~] # Grep bash $ </etc/passwd> result2.txt

[Root @ localhost ~] # Cat result1.txt

[Root @ localhost ~] # Cat result2.txt

[Root @ localhost ~] # Grep root </etc/passwd> result2.txt

[Root @ localhost ~] # Cat result2.txt

Write this first. You can understand these commands and apply them to the actual situation through more hands-on practices.