Procedure. Change to the directory specified by the string s. `Tilde expansion' is allowed.

Returns the current directory as a string.

System(c) : -> RngIntElt

Procedure or function. Execute the system command specified by the string c. If used as a function rather than a procedure, also returns the system command's return value as an integer; this can be used for error-checking.

Execute the given command in the Unix shell then return to Magma. Note that this type of shell escape (contrary to the one using a System call) takes place entirely outside Magma and does not show up in Magma's history.