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Full Discussion: BASH Corrupts Files?
Top Forums Shell Programming and Scripting BASH Corrupts Files? Post 302942722 by Don Cragun on Thursday 30th of April 2015 07:16:32 PM
Old 04-30-2015
That isn't a bash ism. The set -C (aka set -o noclobber) option and its interaction with the:
Code:
fd> file

and:
Code:
fd>| file

redirection operators is required in all POSIX conforming shells...
Code:
#!/bin/bash
options=$(set +o)	# Save current shell options
set -C			# Set noclobber option (synonym for "set -o noclobber"
if > xyzzy		# Fail if file already exists
then	echo '> xyzzy succeeded'
else	echo '> xyzzy failed'
fi
if > xyzzy		# Fail if file already exists
then	echo '2nd > xyzzy succeeded'
else	echo '2nd > xyzzy failed'
fi
if >| xyzzy		# Succeed even if file already exists (as long as you
			# have write permission)
then	echo '>| xyzzy succeeded'
else	echo '>| xyzzy failed'
fi
$options		# Reset original shell options
rm -f xyzzy		# Remove test file

produces output similar to:
Code:
> xyzzy succeeded
tester: line 8: xyzzy: cannot overwrite existing file
2nd > xyzzy failed
>| xyzzy succeeded

I said similar to because the format of the diagnostic message can vary slightly from shell to shell and system to system.
These 2 Users Gave Thanks to Don Cragun For This Post:
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LEARN ABOUT HPUX

killall

killall(1M)															       killall(1M)

NAME

       killall - kill all active processes

SYNOPSIS

       [signal]

DESCRIPTION

       is a procedure used by to kill all active processes not directly related to the shutdown procedure.

       is chiefly used to terminate all processes with open files so that the mounted file systems are no longer busy and can be unmounted.  sends
       the specified signal to all user processes in the system, with the following exceptions:

	      the process;

	      all processes (including background processes) associated with the terminal from which was invoked;

	      any process, if owned by

	      any process, if owned by

	      any process;

	      any process;

	      any process.

       obtains its process information from and therefore may not be able to perfectly identify which processes to signal (see ps(1)).

       If no signal is specified, a default of (kill) is used.

       is invoked automatically by The use of is recommended over using by itself (see shutdown(1M)).

FILES

SEE ALSO

       fuser(1M), kill(1), ps(1), shutdown(1M), signal(5).

STANDARDS CONFORMANCE

																       killall(1M)
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