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'