at reminder script Post: 302561633

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Homework and Emergencies Homework & Coursework Questions at reminder script Post 302561633 by Corona688 on Tuesday 4th of October 2011 04:23:26 PM

10-04-2011

Registered User

"$" variables are likely being substituted before the script is run, so $inputline never changes. You have to escape it with \.

This !! business is strange as well. On my system, that tells it to end the here document on 'man write', since that's the command I ran last.

Code:

at -k $TIME <<EOF
who | cut -c1-20 | grep $LOGNAME | cut -c12-20 | cat > ~/tmp
while read inputline
do
        write $LOGNAME \$inputline < ~/Msgs/message.$$ #|| mail \$inputline < ~/Msgs/message.$$
done < ~/tmp
rm -r ~/Msgs
rm -r ~/tmp
exit 0
EOF

That's a useless use of cat, by the way. Any command can be redirected to file, not just cat -- so leave off the cat and send your last cut into a file, cut -c12-20 > ~/tmp

That's also a useless use of a temp file. You can just feed cut's output directly into the while loop with no intervening file: a | b | c | while read LINE ; do stuff ; done

You never did redirect write's stderr to >dev/null like write ... 2>/dev/null to throw away the messages.

Show me what your who output looks like, and I'll find a more elegant way to get what you want than cut | grep | cut | cat, too.

Corona688

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escape

escape(1)							Mail Avenger 0.8.3							 escape(1)

NAME

       escape - escape shell special characters in a string

SYNOPSIS

       escape string

DESCRIPTION

       escape prepends a "" character to all shell special characters in string, making it safe to compose a shell command with the result.

EXAMPLES

       The following is a contrived example showing how one can unintentionally end up executing the contents of a string:

	   $ var='; echo gotcha!'
	   $ eval echo hi $var
	   hi
	   gotcha!
	   $

       Using escape, one can avoid executing the contents of $var:

	   $ eval echo hi `escape "$var"`
	   hi ; echo gotcha!
	   $

       A less contrived example is passing arguments to Mail Avenger bodytest commands containing possibly unsafe environment variables.  For
       example, you might write a hypothetical reject_bcc script to reject mail not explicitly addressed to the recipient:

	   #!/bin/sh
	   formail -x to -x cc -x resent-to -x resent-cc 
	       | fgrep "$1" > /dev/null 
		   && exit 0
	   echo "<$1>.. address does not accept blind carbon copies"
	   exit 100

       To invoke this script, passing it the recipient address as an argument, you would need to put the following in your Mail Avenger rcpt
       script:

	   bodytest reject_bcc `escape "$RECIPIENT"`

SEE ALSO

       avenger(1),

       The Mail Avenger home page: <http://www.mailavenger.org/>.

BUGS

       escape is designed for the Bourne shell, which is what Mail Avenger scripts use.  escape might or might not work with other shells.

AUTHOR

       David Mazieres

Mail Avenger 0.8.3						    2012-04-05								 escape(1)