Open a File
open <file-name> # open specified file
open index.html
open -a "<app-name>" <file-name> # open with specified app
open -a "Google Chrome" index.html
Open Folder
open . # open the current directory on finder
Open Text Files in the Terminal
cat <file-name> # open short text file
less <file-name> # open long text file
# to search in press / and type then enter
Removing a File or Directory
rm <file-name> # remove the specified file
rm <file1-name> <file2-name> # I can remove multiple file on the same command-line
rm -i <file-name> # -i flag act as a pause button. if I am not sure what I am doing, I mostly use that flag.
rmdir <directory-name> # remove specified empty directory
rm -R <directory-name> # remove the directory and the all files in that directory