Oct 22, 2011 · su lets you switch user so that you're actually logged in as root. sudo -s runs a shell with root privileges. sudo -i also acquires the root user's environment. To see the difference between su and sudo -s, do cd ~ and then pwd after each of them. In the first case, you'll be in root's home directory, because you're root.

su - switches to the superuser and sets up the environment so that it looks like they logged in directly. su root switches to the user named root and doesn't simulate directly logging in. If the superuser is named root, then su and su root are equivalent (and don't simulate directly logging in), as are su - and su - root (which do).

Feb 7, 2011 · su - username sets up the shell environment as if it were a clean login as the specified user, it access and use specified users environment variables, su username just starts a shell with current environment settings for the specified user. If username is not specified with su and su -, the root account is implied as default.

Aug 22, 2018 · Secondly: sudo -i and su - do the same thing (su - is equivalent to su --login), using different authorization mechanism: su verifies the password for the root account, while sudo verifies the password for your current user account and also verifies that your current user account is allowed to run administrative operations according to the /etc/sudoers policy.

su - means environment variables will be reset to root and su means environment variables as old user. for example: root's home directory if you use su - or old user home directory if you use su . sudo ( s uper u ser do ) is a command-line utility that allows users to run programs with the security privileges of another user, by default is ...

Oct 7, 2013 · If you write a password in a command like su <username> -p <password>, it would be stored in plain text in your bash history. This is certainly a huge security issue. If you need to run commands with su (or sudo) in an automated way, write a shellscript containig the commands without su or sudo and run su <username> script.sh

那个慢啊，可是谁又不是这样过来的呢？学习，不管是英语学习、建筑学习，都是要讲究方式方法的，只有不断总结，不断反思，举一反三，才能够快速成长。关于su的学习，尤其是建筑学适用的针对性的su学习是一个系统工程，不可能一个答案能讲完的。

$ sudo su -c whoami nobody [sudo] password for oli: nobody When your command takes arguments you need to quote it. If you don't, strange things will occur. Here I am —as root— trying to create a directory in /home/oli (as oli) without quoting the full command: # su -c mkdir /home/oli/java oli No passwd entry for user '/home/oli/java'

su asks for the password of the account you're trying to login. It's usage (simplified): su username When omitting username, the username default to root. Since the root password is disabled by default on Ubuntu, no password will be valid. The preferred way to run root commands is not through a su shell, but with sudo as in: sudo mount /dev ...

Jul 24, 2017 · The su executable has a special permission bit on it, called the "set-user-ID bit" or "setuid" which causes it to execute such that the effective user ID of the process is that of the owner of that executable file. If su successfully authenticates, it then executes a new shell.