• Version 3.5 and earlier: shellreadonly variable not available.
  • Version 4.0 and later: shellreadonly variable available.


The variable shellreadonly contains a list of environment variables that pbsh and pbksh set to read-only at startup time. If the variable does not exist at start up time, then its entry is ignored. pbsh and pbksh use this variable at startup time.

shellreadonly = list;

A list of environment variables.

if (pbclientmode == "shell start")
shellreadonly = {"PATH", "IFS", "SHELL", "ENV"};