Name
trap
Synopsis
trap [ [commands
]signals
] trap -p trap -l
Execute commands if any
signals are received. The second form is
specific to Bash and ksh93; it
prints the current trap settings in a form suitable for rereading
later. The third form is specific to Bash; it lists all signals
and their numbers, like kill
-l
.
Common signals include EXIT
(0), HUP
(1), INT
(2), and TERM
(15). Multiple commands must be
quoted as a group and separated by semicolons internally. If
commands is the null string (i.e., trap ""
signals
), signals
are ignored by the shell. If commands are
omitted entirely, reset processing of specified signals to the
default action. Bash and ksh93:
if commands is “-”, reset
signals to their initial defaults.
If both commands and signals are omitted, list current trap assignments. See the Examples here and in exec.
Signals
A list of signal names, numbers, and meanings were given
earlier, in the kill entry in
Chapter 2. The shells allow
you to use either the signal number, or the signal name (without
the SIG
prefix). In addition,
the shells support “pseudo-signals,” signal names or numbers that
aren’t real operating system signals but which direct the shell to
perform a specific action. These signals are:
|
Execution of any command. |
|
Nonzero exit status. |
|
Exit from shell (usually when shell script finishes). |
|
Same as |
|
A key has been read in |
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