# Bash Scripting Cheatsheet

 ### For giving read/write/execute permission to user and r/x permission to "groups" and "others":
`chmod 755 script.sh`  

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 ### For checking a command type (if its a shell built in command or a binary):
`type echo`  OR `type -a echo`
`-a` flag displays the list in order in which the command will execute.  

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 ### For getting information about commands that are shell builtin like "echo", we can use:
`help echo`  

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### For getting info about commands which are not shell builtins like "uptime", we can use:
`man uptime`  

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### Must use double quotes for using variables in strings.
For Example:  If we have a variable named "x",
`echo "$x"` will work. But `echo '$x'` won't because it will treat it as a string.

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> By convention, Variables must be all **UPPERCASE**.  

Also should put a **header comment **in beginning of script which defines working of the script.

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### We can check for root privilages when our script includes commands that need root privilages.
```
if [[ $UID -eq 0 ]]
then
  echo "You are Root"
else
  echo "You are not Root"
fi
```
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