Delete whitespace in each begin of line of file, using bash

Question

How i can delete whitespace in each line of file, using bash For instance, file1.txt. Before:

  gg g
 gg g
t  ttt

after:

gg         


        

Answer 1

tr(delete all whitespaces):

$ tr -d ' ' output.txt
$ mv output.txt input.txt

sed(delete leading whitespaces)

$ sed -i 's/^ *//' input.txt