escape(1)                     Mail Avenger 0.8.1                     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 0.8.1                2010-04-12                         escape(1)
