check file or user script assignment problems - linux

Question

Below is the assignment for the bash shell script I'm writing. I'm having a
problem with -u information being output even though I am using the -f option.
This class is a beginner class, so please bear with me. Would be grateful to
have some input on my code. Thanks for taking the time to check this out if you
do.
Here is the sample output:
[***#***]$ chk3 -f share
share is a directory and it is readable | writable | executable | abecker is
currently logged in their home directory is /students/abecker
Here is the usage
chk -f filepath
If filepath exists, output in readable sentences
if it is a symbolic link, say so. You do not have to continue and report the
permissions.
if it doesn't exist, say so. Don't continue to report the permissions
report what it is: file, directory, or something else, and continue to
report the permissions:
report what combination of read, write and execute access rights your
program has for the data. Note that this is dependent on who runs your
program. Do not attempt to do this by looking at the permissions as output
by ls -l. You must use the test operators to do this.
If filepath does not exist (and is not a symbolic link), your program should
report this instead in an informative error message. In this case, you
should exit with an error.
chk -u user
If the user exists on the system, report
the path to the user's home directory
if the user is currently logged in, say so. Otherwise, report when they last
logged in. (Take some care so that this is generated reliably and quickly.)
If the user doesn't exist, report this in an informative error message, and
exit with an error.
Here is my code
#!/bin/bash
if [ $# -gt 2 ]
then
echo "only 2 aruments can be used"
exit 1
fi
if [ "$1" != '-f' -a "$1" != '-u' ]
then
echo "first argument must be -f or -u"
exit 1
fi
if [ "$1" = '-f' -a $# -ne 2 ]
then
echo 'Usage: chk -f [FILEPATH]'
exit 1
fi
if [ "$1" = '-f' ]
then
FILEPATH=$2
fi
if [ -L "$FILEPATH" ]
then
echo "$FILEPATH is a symbolic link"
exit 0
elif [ -d "$FILEPATH" ]
then
echo -e "$(basename "$FILEPATH") is a directory and it is \c"
elif [ -f "$FILEPATH" ]
then
echo -e "$(basename "$FILEPATH") is a file and it is \c"
else
echo "I cannot determine what $(basename "$FILEPATH") is"
exit 1
fi
if [ -r "$FILEPATH" ]
then
echo -e "readable | \c"
fi
if [ -w "$FILEPATH" ]
then
echo -e "writable | \c"
fi
if [ -x "$FILEPATH" ]
then
echo -e "executable | \c"
fi
if [ "$1" = '-u' -a $# -eq 1 ]
then
USER=$LOGNAME
elif [ "$1" = '-u' -a $# -eq 2 ]
then
USER=$2
fi
USERINFO=$(grep "^$USER:" /etc/passwd)
if ! grep "^$USER:" /etc/passwd > /dev/null
then
echo "$USER cannot be found on this system"
exit 1
fi
if ! who | grep "^$USER " > /dev/null
then
echo "$USER is not currently logged on and last logged on"
echo "$(last -1 "$USER")"
exit 0
else
echo "$USER is currently logged in their home directory is"
echo "$(echo "$USERINFO" | awk -F":" '{print $6}')"
fi

Answer 1

You're not putting the processing of different options into different blocks; the code simply passes through everything for all options.
e.g. for the -f option, you have:
if [ "$1" = '-f' ]
then
FILEPATH=$2
fi
and then process all the options for filepath, without putting them into the if statement, so if you pass in either -f or -u, it always passes into the code:
if [ -L "$FILEPATH" ]
then
echo "$FILEPATH is a symbolic link"
exit 0
elif
If you don't want to break your program into functions, what you want to do is put all the code relating to processing the -f option into the same if-statement, somewhat like:
if [ "$1" = '-f' ]
then
FILEPATH=$2
if [ -L "$FILEPATH" ]
then
echo "$FILEPATH is a symbolic link"
exit 0
elif [ -d "$FILEPATH" ]
then
echo -e "$(basename "$FILEPATH") is a directory and it is \c"
elif [ -f "$FILEPATH" ]
then
echo -e "$(basename "$FILEPATH") is a file and it is \c"
else
echo "I cannot determine what $(basename "$FILEPATH") is"
exit 1
fi
if [ -r "$FILEPATH" ]
then
echo -e "readable | \c"
fi
if [ -w "$FILEPATH" ]
then
echo -e "writable | \c"
fi
if [ -x "$FILEPATH" ]
then
echo -e "executable | \c"
fi
fi # if [ "$1" = '-f' ]
Similarly for the -u option, you need to break it into multiple statements and then process all the options for the statement:
if [ "$1" = 'u' ]
then
if [ $# -eq 1 ]
then
USER=$LOGNAME
elif [ $# -eq 2 ]
then
USER=$2
fi
USERINFO=$(grep "^$USER:" /etc/passwd)
if ! grep "^$USER:" /etc/passwd > /dev/null
then
echo "$USER cannot be found on this system"
exit 1
fi
if ! who | grep "^$USER " > /dev/null
then
echo "$USER is not currently logged on and last logged on"
echo "$(last -1 "$USER")"
exit 0
else
echo "$USER is currently logged in their home directory is"
echo "$(echo "$USERINFO" | awk -F":" '{print $6}')"
fi
fi # if [ "$1" = '-u' ]
I would, however recommend putting the code that acts on the options into shell functions, which makes it much easier to read the code; e.g.
filepath() {
FILEPATH="$1"
if [ -L "$FILEPATH" ]
then
echo "$FILEPATH is a symbolic link"
exit 0
elif [ -d "$FILEPATH" ]
then
echo -e "$(basename "$FILEPATH") is a directory and it is \c"
elif [ -f "$FILEPATH" ]
then
echo -e "$(basename "$FILEPATH") is a file and it is \c"
else
echo "I cannot determine what $(basename "$FILEPATH") is"
exit 1
fi
if [ -r "$FILEPATH" ]
then
echo -e "readable | \c"
fi
if [ -w "$FILEPATH" ]
then
echo -e "writable | \c"
fi
if [ -x "$FILEPATH" ]
then
echo -e "executable | \c"
fi
}
And then for the processing code:
if [ "$1" = '-f' ]
then
filepath "$2"
fi
and something similar for the -u option.