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  man pages->Tru64 Unix man pages -> wait (1)              



NAME    [Toc]    [Back]

       wait - Awaits process completion

SYNOPSIS    [Toc]    [Back]

       wait [pid]


       The  C shell  has  a built-in version of the wait command.
       If you are using the C shell, and want to  guarantee  that
       you are using the command described here, you must specify
       the full path /usr/bin/wait.   See  the  csh(1)  reference
       page for a description of the built-in command.

STANDARDS    [Toc]    [Back]

       Interfaces  documented  on  this reference page conform to
       industry standards as follows:

       wait:  XCU5.0

       Refer to the standards(5) reference page for more information
 about industry standards and associated tags.

OPTIONS    [Toc]    [Back]


OPERANDS    [Toc]    [Back]

       One of the following: The unsigned decimal integer process
       ID of a command, for which the utility is to wait for  the
       termination.  A job control job ID that identifies a background
 process group to be waited for. The job control job
       ID  notation is applicable only for invocations of wait in
       the current shell execution environment.  The exit  status
       of wait is determined by the last command in the pipeline.

DESCRIPTION    [Toc]    [Back]

       When an asynchronous list is started  by  the  shell,  the
       process  ID  of  the  last  command in each element of the
       asynchronous list becomes known in the current shell  execution

       If  the wait utility is invoked with no operands, it waits
       until all process IDs known to  the  invoking  shell  have
       terminated and exits with a zero exit status.

       If  one  or more pid operands are specified that represent
       known process IDs, the wait utility  waits  until  all  of
       them  have  terminated.  If  one  or more pid operands are
       specified that represent unknown process IDs, wait  treats
       them  as  if  they were known process IDs that exited with
       exit status 127. The exit  status  returned  by  the  wait
       utility is the exit status of the process requested by the
       last pid operand.

       The known process IDs are applicable only for  invocations
       of wait in the current shell execution environment.

RESTRICTIONS    [Toc]    [Back]

       If wait is called in a subshell or separate utility execution
 environment, such as one of the following, it returns
       immediately because there are no known process IDs to wait
       for in those environments:

              (wait) nohup wait ...  find . -exec wait ... \;  If
              the  exit status of wait is greater than 128, there
              is no way  for  the  application  to  know  if  the
              waited-for  process  exited  with that value or was
              killed by a signal.  Since most utilities exit with
              small values, there is seldom any ambiguity.

EXIT STATUS    [Toc]    [Back]

       If one or more parameters were specified, all of them have
       terminated or were not known by the  invoking  shell,  and
       the  status of the last parameter specified is known, then
       the exit status of wait is the exit status information  of
       the command indicated by the last parameter specified.  If
       the process terminated abnormally due to the receipt of  a
       signal,  the  exit  status is greater than 128 and is distinct
 from the exit status  generated  by  other  signals.
       (See  the  kill  -l  option.)  Otherwise, the wait utility
       exits with one of the following values: The  wait  utility
       was  invoked with no operands and all process IDs known by
       the invoking shell  have  terminated.   The  wait  utility
       detected an error.  The command identified by the last pid
       operand specified is unknown.

EXAMPLES    [Toc]    [Back]

       Although the exact value used when a process is terminated
       by  a  signal is unspecified, if it is known that a signal
       terminated a process, a script can still  reliably  figure
       out  which  signal  using  kill  as shown by the following

              sleep 1000& pid=$!  kill -kill $pid wait $pid  echo
              $pid  was  terminated by a SIG$(kill -l $?) signal.
              If either sequence of commands shown on  the  first
              two  lines is run in less than 31 seconds either of
              the commands shown on lines 3 and 4 will return the
              exit status of the second sleep in the pipeline:

              sleep  257  |  sleep  31  & jobs -l %% wait <pid of
              sleep 31> wait %%


       The following environment variables affect  the  execution
       of  wait:  Provides a default value for the internationalization
 variables that are unset or null. If LANG is unset
       or  null,  the corresponding value from the default locale
       is used.  If any  of  the  internationalization  variables
       contain an invalid setting, the utility behaves as if none
       of the variables had been defined.  If set to a  non-empty
       string value, overrides the values of all the other internationalization
 variables.  Determines the locale for  the
       interpretation of sequences of bytes of text data as characters
 (for example, single-byte as opposed  to  multibyte
       characters  in  arguments).  Determines the locale used to
       affect the format  and  contents  of  diagnostic  messages
       written  to  standard  error.   Determines the location of
       message catalogues for the processing of LC_MESSAGES.

SEE ALSO    [Toc]    [Back]

       Commands:  bg(1), csh(1), fg(1), jobs(1), kill(1), ksh(1),

       Functions:  wait(2)

       Standards:  standards(5)

[ Back ]
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