execute a command as another user

-i [command]
            The -i (simulate initial login) option runs the shell specified by the password database
            entry of the target user as a login shell.  This means that login-specific resource files
            such as .profile or .login will be read by the shell.  If a command is specified, it is
            passed to the shell for execution via the shell's -c option.  If no command is specified, an
            interactive shell is executed.  sudo attempts to change to that user's home directory before
            running the shell.  The security policy shall initialize the environment to a minimal set of
            variables, similar to what is present when a user logs in.  The Command Environment section
            in the sudoers(5) manual documents how the -i option affects the environment in which a
            command is run when the sudoers policy is in use.

-P          The -P (preserve group vector) option causes sudo to preserve the invoking user's group
            vector unaltered.  By default, the sudoers policy will initialize the group vector to the
            list of groups the target user is in.  The real and effective group IDs, however, are still
            set to match the target user.

-n          The -n (non-interactive) option prevents sudo from prompting the user for a password.  If a
            password is required for the command to run, sudo will display an error messages and exit.

Pipelines
    A  pipeline is a sequence of one or more commands separated by one of the control operators | or |&.  The
    format for a pipeline is:

           [time [-p]] [ ! ] command [ [|⎪|&] command2 ... ]

    The standard output of command is connected  via  a  pipe  to  the  standard  input  of  command2.   This
    connection  is performed before any redirections specified by the command (see REDIRECTION below).  If |&
    is used, the standard error of command is connected to command2's standard input through the pipe; it  is
    shorthand  for  2>&1  |.   This  implicit  redirection  of  the  standard  error  is  performed after any
    redirections specified by the command.

    The return status of a pipeline is the exit status of the last command, unless  the  pipefail  option  is
    enabled.   If  pipefail  is  enabled,  the  pipeline's return status is the value of the last (rightmost)
    command to exit with a non-zero status, or zero if all commands exit successfully.  If the reserved  word
    !   precedes  a  pipeline, the exit status of that pipeline is the logical negation of the exit status as
    described above.  The shell waits for all commands in the pipeline to terminate before returning a value.

    If the time reserved word precedes a pipeline, the elapsed as well as user and system  time  consumed  by
    its execution are reported when the pipeline terminates.  The -p option changes the output format to that
    specified by POSIX.  When the shell is in posix mode, it does not recognize time as a  reserved  word  if
    the  next  token begins with a `-'.  The TIMEFORMAT variable may be set to a format string that specifies
    how the timing information should be displayed; see the description of TIMEFORMAT under  Shell  Variables
    below.

    When the shell is in posix mode, time may be followed by a newline.  In this case, the shell displays the
    total user and system time consumed by the shell and its children.  The TIMEFORMAT variable may  be  used
    to specify the format of the time information.

    Each command in a pipeline is executed as a separate process (i.e., in a subshell).

print lines matching a pattern

grep searches the named input FILEs (or standard input if no files are named, or if a single hyphen-minus
(-) is given as file name) for lines containing a match to the given PATTERN.  By  default,  grep  prints
the matching lines.