Question

I need to read a file with bash and remove the request line? Some similar to
pop/push functions.

How can i do it?

Answer 1

You can use sed to delete specific line numbers or lines that match a given pattern:

$ cat file
line 1
line 2 
line 3 
line 4
line 5

$ sed -i '3d' file             # Delete the 3rd line
line 1
line 2 
line 4
line 5    

$ sed -i '/^line 4$/d' file    # Delete the line that matches the pattern
line 1
line 2 
line 3 
line 5


$ sed '$d' file                # Delete the last line in the file
line 1
line 2 
line 3 
line 4

You will not be able to push these lines back however..