Shell Programming and Scripting

Hi have set a command line argument where the user enters the filename.

I have set a condition that if the command line is null (user just enters return), the script will exit (with an error message).

However, what if the user types something and the file isn't found. How will I go about defining that condition?

Thanks

see the "test" man page for the various options available.

Code:

if [ -e $file ]

or

Code:

if [ -f $file ]

or

Code:

if [ -r $file ]

or in your case since you want the complement of these conditions:

Code:

if [ ! -e $file ]

or

Code:

if [ ! -f $file ]

or

Code:

if [ ! -r $file ]

or -x to test if an executable file exists

Thanks for the help guys.. after viewing the man "test", I have come up with this:

if test -z $file -o ! -a $file

the -z bit is for when the user simply hits return and doesn't enter anything at the command prompt

the ! -a bit is if the file does not exist.

I have tried the above and it causes some problems:
- it doesn't catch the error if the user just hits return (i.e. enters nothing)
- if 2+ words are entered the above doesn't catch it

Valid files are allowed to proceed.

Any suggestions are welcome

thanks

check for number of arguments?

Code:

echo $#
if [ $# -eq 0 ];then
 echo "No arguments "
fi

Code:

if [ $# -eq 0 ]
then
    echo "Exiting.  No filename argument entered"
    exit 1
fi

if [ $# -gt 1 ]
then
   echo "Exiting.  Expecting a single filename argument"
   exit 1
fi

if [ ! -e $1 ]
then
   echo "Exiting.  File does not exist."
   exit 1
fi

if [ ! -f $1 ]
then
   echo "Exiting.  File is not a regular file"
   exit 1
fi

Thanks for the help. I have tried what fpmurphy has written (excluding the regular file test) but every time I enter a valid filename of a file that exists, I keep getting the "Exiting. No filename argument entered" error.

In fact no matter what I type, the above condition catches it. Any idea why that is?

if I remove the above and just leave the other conditions, non-existent files that have a single filename are caught but entering nothing doesn't and entering two worded filenames still doesn't get caught.

The $# conditions ain't working as they should. the ! -e $file is the only condition working properly.

This is puzzling! the $file is read and I enter the conditions directly after it. :S