2.11 Faster ksh and bash Startup with $- Test

Do you use the Korn shell - and does your account have an "ENV file" (2.2) (a startup file named in the ENV environment variable)? bash users, you probably have setup files like .bashrc or .bash_login. You might have the same problem (2.9) that C shell users have with .cshrc: noninteractive shells read aliases and other lines that you want to be read only by interactive shells. Speed up your file by adding a test like this:

case	case $- in *i*);; *) return 0;; esac # COMMANDS BELOW THIS LINE WILL ONLY BE RUN BY INTERACTIVE SHELLS: ...

The test checks to see if the shell's -i option is set. If it isn't, the return 0 quits the file.