The Helloword of the shell

The Helloword of the shell
Cd/bin
Ls-l | Find-name SH
Ls-l | FIND-NAMD Bash

Ls-l | Grep-r sh sh is actually pointing to dash
lrwxrwxrwx 1 root root 4 2014-12-11 03:13 sh, dash
Ls-l | Grep-r Bash

CD ~
mkdir Shell

VI hello.sh
#!/bin/bash//fixed notation, equivalent to introducing
Echo ' Helloword '

Ls-l
sudo chmod u+w hello.sh//Let the owner of the file have hello.sh Execute permission
./hello.sh

Declare a temporary variable in the current window:
Hi=sniper.hi
Echo $hi

Pstree
Gnome-terminal─┬─bash───pstree
│├─bash
│├─gnome-pty-helpe
│└─2*[{gnome-terminal}]

Bash//Start a new shell subprocess, Bash command, start for subprocess, note the path difference
Pstree
Gnome-terminal─┬─bash───bash───pstree
│├─bash
│├─gnome-pty-helpe
│└─2*[{gnome-terminal}]

Go back to the previous level process exit

Problems encountered:
HELLO.SH//Such direct execution does not

hi = Sniper.hi//assignment in the shell, no spaces need to be written Hi=sniper.hi

The Helloword of the shell