NAME

trap, onintr - shell built-in functions to respond to (hardware) signals SYNOPSIS

sh

trap [ argument n [ n2 . . . ]] csh

onintr [ -| label] ksh

. trap [ arg sig [ sig2 . . . ]] DESCRIPTION

sh

The trap command argument is to be read and executed when the shell receives numeric or symbolic signal(s) (n). (Note: argument is scanned once when the trap is set and once when the trap is taken.) Trap commands are executed in order of signal number or corresponding symbolic names. Any attempt to set a trap on a signal that was ignored on entry to the current shell is ineffective. An attempt to trap on signal 11 (memory fault) produces an error. If argument is absent all trap(s) n are reset to their original values. If argument is the null string this signal is ignored by the shell and by the commands it invokes. If n is 0 the command argument is executed on exit from the shell. The trap command with no arguments prints a list of commands associated with each signal number. csh

onintr controls the action of the shell on interrupts. With no arguments, onintr restores the default action of the shell on interrupts. (The shell terminates shell scripts and returns to the terminal command input level). With the - argument, the shell ignores all interrupts. With a label argument, the shell executes a goto label when an interrupt is received or a child process terminates because it was interrupted. ksh

trap uses arg as a command to be read and executed when the shell receives signal(s) sig. (Note that arg is scanned once when the trap is set and once when the trap is taken.) Each sig can be given as a number or as the name of the signal. trap commands are executed in order of signal number. Any attempt to set a trap on a signal that was ignored on entry to the current shell is ineffective. If arg is omitted or is -, then the trap(s) for each sig are reset to their original values. If arg is the null (the empty string, e.g., "" ) string then this signal is ignored by the shell and by the commands it invokes. If sig is ERR then arg will be executed whenever a command has a non-zero exit status. If sig is DEBUG then arg will be executed after each command. If sig is 0 or EXIT for a trap set outside any function then the command arg is executed on exit from the shell. The trap command with no arguments prints a list of commands associated with each signal number. On this man page, ksh(1) commands that are preceded by one or two . (daggers) are treated specially in the following ways: ATTRIBUTES

See attributes(5) for descriptions of the following attributes: ATTRIBUTE TYPEATTRIBUTE VALUE AvailabilitySUNWcsu SEE ALSO

csh(1), exit(1), ksh(1), sh(1), attributes(5