5.1.1 Reserved words
In JP1/Advanced Shell, special words and phrases that are used in control statements in job definition scripts are registered as reserved words. A reserved word has a special meaning when it is used as the first word of a command and is always recognized as a reserved word (unless it is not enclosed in quotation marks). A reserved word used as the second or any subsequent word is treated as a normal variable. Therefore, special attention is important when you use the reserved words.
To use reserved words, use the standard shell commands command -V and whence -v. For details about the command and whence commands, see command command (executes a command) and whence command (displays how character strings would be interpreted if used as commands) in 9.3 Standard shell commands.
The following are the reserved words:
! [[ { } case do done elif else esac fi for function if in select then time until while