Problem understanding Paths Post: 302646945

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Top Forums UNIX for Dummies Questions & Answers Problem understanding Paths Post 302646945 by Chasman78 on Saturday 26th of May 2012 02:40:42 PM

05-26-2012

Registered User

I forgot to mention that I get this error message after entering ./inpath echo at the command line:

./inpath: line 48: checkforCmdInPath: command not found

---------- Post updated at 02:38 PM ---------- Previous update was at 02:37 PM ----------

Sorry, I meant that I had already done those two things before even writing this post.

---------- Post updated at 02:40 PM ---------- Previous update was at 02:38 PM ----------

Here's my actual code (I'm embarrassed I didn't think to just cut and paste like normal):

Code:

#!/bin/sh
# inpath - Verifies that a specified program is either valid as is, 
# or that it can be found in the PATH directory list.

in_path()
{
	# Given a command and the PATH, try to find the command.  Returns
	# 0 if found and executable, 1 if not.  Note that this temporarily modifies 
	# the IFS (input field separator) but restores it upon completion.

	cmd=$1		path=$2		retval=1
	oldIFS=$IFS	IFS=":"

	for directory in $path
	do
		if [ -x $directory/$cmd ] ; then
		retval=0   # if we're here, we found $cmd in $directory
		fi
	done
	IFS=$oldIFS
	return $retval
}

checkForCmdInPath()
{
	var=$1
	# The variable slicing notation in the following conditional
	# needs some explanation: ${var#expr} returns everything after
	# the math for 'expr' in the variable value (if any), and 
	# ${var%espr} returns everything that doesn't match (in this
	# case, just the very first character.  You can also do this in
	# Bash with ${var:0:1}, and you could use cut too: cut -c1.

	if [ "$var" != "" ] ; then
		if [ "${var%${var#?}}" = "/" ] ; then
			if [ ! -x $var ] ; then
				return 1
			fi
		elif ! in_path $var $PATH ; then
			return 2
		fi
	fi
}
	if [ $# -ne 1 ] ; then
		echo "Usage: $0 comand" >&2 ; exit 1
	fi

	checkforCmdInPath "$1"
	case $? in
		0) echo "$1 found in PATH"	;;
		1) echo "$1 not found or not executable"	;;
		2) echo "$1 not found in PATH"	;;
	esac

	exit 0

Chasman78

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LEARN ABOUT OPENSOLARIS

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)