Novell LINUX ENTERPRISE 11 - HIGH AVAILABILITY, Руководство пользователя, Страница: 194 / 298

Syntax/Description Command
test [expr]
test
Exits with a status of 0 (true) or 1 (false) depending on the evaluation
of
EXPR
. Expressions may be unary or binary. Unary expressions are
often used to examine the status of a file. There are string operators
as well, and numeric comparison operators.
time [-p] PIPELINE
time
Execute
PIPELINE
and print a summary of the real time, user CPU
time, and system CPU time spent executing
PIPELINE
when it termi-
nates. The return status is the return status of PIPELINE. The
-p
option
prints the timing summary in a slightly different format. This uses the
value of the TIMEFORMAT variable as the output format.
times
times
Print the accumulated user and system times for processes run from
the shell.
trap [-lp] [ARG SIGNAL_SPEC ...]
trap
The command
ARG
is to be read and executed when the shell receives
signal(s)
SIGNAL_SPEC
. If
ARG
is absent (and a single
SIGNAL_SPEC
is supplied) or
-
, each specified signal is reset to its
original value. If
ARG
is the null string each
SIGNAL_SPEC
is ignored
by the shell and by the commands it invokes. If a
SIGNAL_SPEC
is
EXIT (0) the command ARG is executed on exit from the shell. If a
SIGNAL_SPEC
is DEBUG,
ARG
is executed after every simple
command. If the
-p
option is supplied then the trap commands associ-
ated with each
SIGNAL_SPEC
are displayed. If no arguments are
supplied or if only
-p
is given, trap prints the list of commands asso-
ciated with each signal. Each
SIGNAL_SPEC
is either a signal name
in
signal.h
or a signal number. Signal names are case insensitive
and the SIG prefix is optional.
trap -l
prints a list of signal names
and their corresponding numbers. Note that a signal can be sent to the
shell with
kill -signal $$
.
184 High Availability Guide