Merge pull request #1 from bloodysin/msh

if test
Merge pull request #2 from bloodysin/msh

if command script
move parse_line to arguments.c
Merge branch 'master' of github.com:halftan/practice

Conflicts:
	native/msh/exec_if.c
remove envp argument in some functions
add err_handler and util functions
get input from multipled lines