shopt -s nullglob Post: 302254561

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Top Forums Shell Programming and Scripting shopt -s nullglob Post 302254561 by msb65 on Tuesday 4th of November 2008 05:53:14 PM

11-04-2008

Registered User

shopt -s nullglob

Hi,

I am using BASH. In a directory there are files that match either of the following 2 patterns: [AST]*.L1A_[GL]AC* or S*.L1A_MLAC*

I would like to write a script that will include a for loop, where for each file in the directory, a certain function will be performed. For example:

for FILE in [AST]*.L1A_[GL]AC* S*.L1A_MLAC*; do
echo $FILE
done

The content of the directory will be random, and there are 3 potential scenarios: 1) Files of both patterns exist in the directory, 2) Only files of the 1st pattern exist, 3) Only files of the 2nd pattern exist. The last two scenarios are problematic as one of the patterns won't be matched, resulting in my script behaving oddly.

- I believe the way around this is to use the shopt -s nullglob option. Does anyone have any other ideas?

- MAIN QUESTION: Where in the code should I put the shopt -s nullglob and shopt -u nullglob? Of course the shopt -s nullglob should be set immediately before the the beginning of the for loop. But, can the shopt -u nullglob be immediately after the beginning of the for loop (ie):

shopt -s nullglob
for FILE in [AST]*.L1A_[GL]AC* S*.L1A_MLAC*; do
shopt -u nullglob
echo $FILE
done

OR after the conclusion of the for loop (ie):

shopt -s nullglob
for FILE in [AST]*.L1A_[GL]AC* S*.L1A_MLAC*; do
echo $FILE
done
shopt -u nullglob

The reason I ask is because I will of course have more complicated code within the for loop, and only want the shopt nullglob command to affect the pattern matching when calling the for loop.

Thanks for your help.

Mike

msb65

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LEARN ABOUT OSF1

thread_halt_self

thread_halt_self(9r)													      thread_halt_self(9r)

NAME

       thread_halt_self - General: Handles asynchronous traps for self-terminating kernel threads

SYNOPSIS

       void thread_halt_self(
	       void );

ARGUMENTS

       None

DESCRIPTION

       The  thread_halt_self  routine performs the work associated with a variety of asynchronous traps (ASTs) for a kernel thread that terminates
       itself. A kernel thread terminates itself (or one kernel thread terminates another kernel thread) by calling the thread_terminate routine.

       The thread_halt_self routine examines the AST-related member of the thread structure pointer associated with the kernel thread  that  wants
       to terminate itself. This thread structure pointer was returned in a previous call to kernel_isrthread or kernel_thread_w_arg and passed by
       you to the thread_terminate routine. This AST-related member is set to a bit that identifies the specific AST  trap  associated	with  this
       kernel  thread.	Based on the AST bit set in this member, thread_halt_self does the appropriate cleanup work before the kernel thread exits
       from the kernel.

NOTES

       A kernel thread that terminates itself must call thread_halt_self immediately after the call to thread_terminate.  The reason for  this	is
       that  thread_terminate  only prepares the self-terminating kernel thread to stop execution. The thread_halt_self routine completes the work
       needed to stop execution of the self-terminating kernel thread by performing the appropriate cleanup work.

RETURN VALUES

       None

SEE ALSO

       Routines: thread_terminate(9r)

															      thread_halt_self(9r)