# LOG > [HTML Version](log_lit.htm) _Updated June 2016, see History_ **LOG \{/n\} ** A-Shell maps DevPPN format file specifications onto host pathnames using the definitions given with the [DEVICE](device_sp.htm.md) statements in miame.ini. On entering A-Shell, your current working directory is translated into your current AMOS login account. If there is no mapping defined, then you enter A-Shell in a logged off state. You may use the LOG command to log in and subsequently change your login account to one with a valid mapping to an existing host machine directory. The implementation of LOG will check for the validity of the PPN, execute any start.cmd command file (unless /N specified), and accept and display [ERSATZ](ersatz_sp.htm.md) names. It does not accept or ask for user names. The user name as returned by the GETJTB subroutine is your user name in the host operating system environment. The _/n _switch disables the normal execution of a start.cmd file in the target directory. _Destination_ may consist of all or part of a device and PPN, or an [ERSATZ](ersatz_sp.htm.md) device. **Examples** LOG SYS: LOG DSK0:\[1,4\] LOG DSK0:1,4 LOG DSK0: LOG 1,4 LOG ,4 LOG MYAPP: **History** 2016 June, A-Shell 6.3.1515: LOG.LIT 3.0(124) now explicitly reports a log failure to the screen.