gw/remsh is a SAP Parameter attribute which is used to control Remote shell command information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
The parameter specifies the call path of the remote shell to start
programs on other hosts.
Specification of a user for remote shell
The system attempts to read the variable USER from the environment.
The value of this variable is transferred to the remote shell with the
option -l <(><<)>user>.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.