Shell

The shell is a command-line interface for running programs.

Also, the vast majority of web servers in the wild run on the linux and the shell is a vital tool for development.

 

ls  =  list the directory

ls -l  =  detailed info

ls -l Documents/*.pdf =show the detailed file which end as .pdf

ls -l Documents/ =  show the long detailed info

 

pwd  =  现在所属的文件夹位置

cd =  进入

cd. . =  父级

ls~ = home directory

 

mkdir =  make a new directory

mkdir Documents/Books

mv 'Documents/*1984.epub'  Documents/Books/

mv Documents/*.epub  Documents/Books/ ==All the .epub file move to the other address

 

 

man +order = check the meaning of order

 

curl =C URL=see URL~explaining the joke

curl 'http://google.com'

curl -L 'http://google.com'

curl is good at downloading the file.

curl -o google.html -L  'http://google.com'

 

Enter a shell command to download https://tinyurl.com/zeyq9vc and save it as the file dictionary.txt. Remember to use the option to follow web redirects.

curl -L -o dictionary.txt  'http://tinyurl.com/zeyq9vc'

 

cat = read the file and output the content = catenate =concatenate=run serval thing together

cat dictionary.txt

 less =less file

 

rm=remove

rm -i

rmdir errorDirectory

 

grep shell dictionary.txt

grep shell dictionary.txt | less

curl -L https://tinyurl.com/zeyq9vc | grep fish

curl -L https://tinyurl.com/zeyq9vc | grep fish | wc -L

 

shell has two variabless.

numbers='one two three'

echo $number

One is internal to the shell program itself.

echo $LINES*$COLUMNS

 

The other kind is called an environment variable.

echo $PATH

Environment variables are shared with programs that you run from within the shell.

One environment variable that is really important is the Path variable. That tells your system where your program Files are.

 

bash_profile

 

man bash

alias

alias ll='ls -la'