9.3 Standard shell commands
The standard shell commands are divided into special built-in commands and regular built-in commands, as shown below. A built-in command is one that is included as part of the shell, and is executed by the shell itself.
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Special built-in commands
If a special built-in command's syntax is invalid, it exits the shell that is executing the command.
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Regular built-in commands
Even if a regular built-in command's syntax is invalid, it does not exit the shell that is executing the command.
- Organization of this section
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continue command (interrupts loop processing and returns to the beginning of the loop)
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echo command (outputs what is specified in arguments to the standard output)
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eval command (concatenates arguments into a command and executes it)
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let command (evaluates the values of arithmetic expressions)
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read command (reads from the standard input and stores the input in variables)
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readonly command (sets the read-only attribute for variables or displays all read-only variables)
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return command (returns from a function or an external script)
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set command (sets shell options, creates an array, or displays variable values)
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test command (determines the value of a conditional expression)
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times command (displays the amount of CPU time used by the shell)
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trap command (specifies the action when signals and forced termination requests are received)
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typeset command (declares explicitly the attributes and values of variables and functions)
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ulimit command (sets limits on system resources) (UNIX only)
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umask command (sets the access permissions for creating a new file) (UNIX only)
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whence command (displays how character strings would be interpreted if used as commands)