Cheat Sheet For Shell

This is a shell cheat sheet to help user

Basic introduction for Unix system

• File's extension is not important in Unix system

Filename Reminders

• Case MaTTerS
• File Extensions (e.g. .txt .doc .docx) don't matter
• Avoid spaces in filenames
• Files starting with '.' are hidden by default
• Backup files created by some editors will be appended with ~

commond

Cat:

• cat filename can directly show you the content of your file.
• cat filename1 filename2 > newfile can put two files into one file
• cat filename1 >> newfile add filename1 into the end of newfile
• cat filename1 > newfile replace the content in newfile using filename

Sudo (Super User do)

• sudo su can make you switch to super user, which has 100% authority.

Touch

• touch used when you just want to creat files but not edit them

Find

• find . -maxdepth 1 -type f/d -iname "name.txt" -size is used to find the file "name.txt".
• find . -maxdepth 1 type f/d not -iname "name.txt" -size is used to find the file is not named "name.txt".

Grep

• grep "keywords" file is used to find the words in the file
• grep -i "keywords" file is used to find the words in the file but not care about case
• grep -n -i "keywords" file is used to find the words in the file but not care about case and give you the line's number

Combine find and grep to do search

• find . -maxdepth 1 -type f/d -iname "name.txt" -exec grep -i -n "function" {} +