Korn Shell: Unix and Linux Programming Manual, Third Edition, The

Invocation

If the shell is invoked by exec(2), and the first character of argument zero ($0) is -, then the shell is assumed to be a login shell and commands are read from /etc/profile and then from either .profile in the current directory or $HOME/.profile, if either file exists. Next, for interactive shells, commands are read from the file named by performing parameter expansion, command substitution, and arithmetic substitution on the value of the environment variable ENV if the file exists. If the -s option is not present and arg is, then a path search is performed on the first arg to determine the name of the script to execute. The script arg must have read permission and any setuid and setgid settings will be ignored. If the script is ...