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Full Discussion: Script in bash that works only some of the time
Top Forums Shell Programming and Scripting Script in bash that works only some of the time Post 302960931 by bakunin on Sunday 22nd of November 2015 06:00:27 AM
Old 11-22-2015
Just an afterthought: if i have gotten correctly what you want to do is 1) wait until a file is there and 2), if it is there wait until "TRL" appears in it.

Such things should be best put into a function, not your main code, if for nothing else than for clarity and readability. The following might not do exactly what you want, take it as a blue print for handling such situations in general:

Code:
#! /bin/bash

pCheckForFile ()
{
fIn="/path/to/file/to/check.for"   # alternatively a filename could be provided as argument
# fIn="$1"                         # alternatively a filename could be provided as argument
chText="TRL"                       # text to check for
iRetVal=1                          # value/error status to return

if [ -f "$fIn" ] ; then
     if grep -q "$chText" "$fIn"
          iRetVal=0
     fi
fi

return iRetVal
}



# main()

while ! pCheckForFile ; do
# while ! pCheckForFile /some/file/to/check; do   # this is the alternative call
     sleep 180
done

doSomething

exit 0

You see, "pCheckForFile()" just does the testing, the main part will just use that, wait as long as necessary and then continue. If, for instance, you would want a background job to wait indefinitely and start some processing once the file is there, then sleep again (sort-of daemon) you could change the main part only to have this:

Code:
#! /bin/bash

pCheckForFile ()
{
<same as above>
}



# main()

while : ; do
     # if pCheckForFile  /some/file/to/check ; then  # alternative, when a filename is provided as argument
     if pCheckForFile ; then
          doSomeThingHere
     fi
     sleep 180
done

exit 0

I hope this helps.

bakunin
This User Gave Thanks to bakunin For This Post:
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LEARN ABOUT HPUX

ntp-wait

ntp-wait(1)							   User Commands						       ntp-wait(1)

NAME

       ntp-wait - Wait for ntpd to stabilize the system clock

SYNOPSIS

       ntp-wait [-flags] [-flag [value]] [--option-name[[=| ]value]]

       All arguments must be options.

DESCRIPTION

       ntp-wait will send at most num-tries queries to ntpd(8), sleeping for secs-between-tries after each status return that says ntpd(8) has not
       yet produced a synchronized and stable system clock.

       ntp-wait will do this quietly, unless the -v flag is provided.  This can be useful at boot time, to delay the  boot  sequence  until  after
       ntpd -g has set the time.

OPTIONS

       -n number, --tries=number
	      Number of times to check ntpd.  This option takes an integer number as its argument.  The default number for this option is:
		   100

		      The maximum number of times we will check ntpd to see if
		      it has been able to synchronize and stabilize the system clock.

       -s secs-between-tries, --sleep=secs-between-tries
	      How  long  to  sleep  between  tries.  This option takes an integer number as its argument.  The default secs-between-tries for this
	      option is:
		   6

		      We will sleep for secs-between-tries after each query
		      of ntpd that returns "the time is not yet stable".

       -v, --verbose
	      Be verbose.

		      By default, ntp-wait is silent.
		      With this option, ntp-wait will provide status information.

       -?, --help
	      Display usage information and exit.

       -!, --more-help
	      Pass the extended usage information through a pager.

       -v [{v|c|n --version [{v|c|n}]}]
	      Output version of program and exit.  The default mode is `v', a simple version.  The `c' mode will print copyright  information  and
	      `n' will print the full copyright notice.

EXIT STATUS

       One of the following exit values will be returned:

       0  (EXIT_SUCCESS)
	      Successful program execution.

       1  (EXIT_FAILURE)
	      The operation failed or the command syntax was not valid.

       70  (EX_SOFTWARE)
	      libopts had an internal operational error.  Please report it to autogen-users@lists.sourceforge.net.  Thank you.

AUTHORS

       Harlan Stenn

NOTES

       This document corresponds to version 4.2.8p13 of NTP.

       This manual page was AutoGen-erated from the ntp-wait option definitions.

ntp (4.2.8p13)							    20 Feb 2019 						       ntp-wait(1)
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