Command Syntax

The shell begins parsing its input by breaking it into words. Words, which are sequences of characters, are delimited by unquoted white-space characters (space, tab and newline) or meta-characters (<, >, |, ;, &, (and)). Aside from delimiting words, spaces and tabs are ignored, while newlines usually delimit commands. The metacharacters are used in building the following tokens: <, <&, <<, >, >&, >>, etc. are used to specify redirections (see Input/Output Redirection below); | is used to create pipelines; |& is used to create co-processes (see Co-Processes later in this appendix); ; is used to separate commands; & is used to create asynchronous pipelines; && and || are used to specify conditional execution; ;; is used in case ...

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