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\section trap trap - perform an action when the shell receives a signal
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\subsection trap-synopsis Synopsis
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<tt>trap [OPTIONS] [[ARG] SIGSPEC ... ]</tt>
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\subsection trap-description Description
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Trap is a shellscript wrapper around the fish event delivery
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framework. It exists for backwards compatibility with Posix
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shells. For other uses, it is recommended to define a <a
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href='index.html#event'>event handler</a>.
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- ARG is the command to be executed on signal delivery
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- SIGSPEC is the name of the signal to trap
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- \c -h or \c --help Display help and exit
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- \c -l or \c --list-signals print a list of signal names
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- \c -p or \c --print print all defined signal handlers
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If ARG and SIGSPEC are both specified, ARG is the command to be
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executed when the signal specified by SIGSPEC is delivered.
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If ARG is absent (and there is a single SIGSPEC) or -, each specified
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signal is reset to its original disposition (the value it had upon
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entrance to the shell). If ARG is the null string the signal
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specified by each SIGSPEC is ignored by the shell and by the commands
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it invokes.
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If ARG is not present and -p has been supplied, then the trap commands
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associated with each SIGSPEC are displayed. If no arguments are
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supplied or if only -p is given, trap prints the list of commands
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associated with each signal.
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Signal names are case insensitive and the SIG prefix is optional.
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The return status is 1 if any SIGSPEC is invalid; otherwise trap
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returns 0.
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