problems with "if"

[cayalee]

hi guys, been absent from here for a while but need some help with creating a script. i've been trying to build a shell script that tests to see if a folder is present and if it is, then copy it to a predefined backup location.
however, it just keeps giving me the following error

if: Expression Syntax

so the way i've built it is like this:

if [ -d /usr/people/cranial4 ]
then
echo "found cranial, preparing to back up"
cp /usr/peoplecranial /mnt/usbdisk/cranialdata
else
echo "cranial not installed, skipping step"
fi

as i understand it, using [ ] is the same as using the test command, and the -d option specifies its a directory. i want it to check whether a program is installed, and if so copy some files. if not, tell me that its not installed and move on.
where am i going wrong? i'm bouncing my head off the wall
thanks in advance guys

[coopstah13]

very strange, I tested script

#!/bin/bash
if [ -d /home/ccooper ]
then
echo "1"
else
echo "0"
fi

very similar to yours, works for me

[cayalee]

it is very weird, i've been building this on ubuntu/DSL and then trying to run it on the work linux (2.4.1 kernel) and it doesn't like it. i can build a similar script using same commands etc on the work machine and it plays nicely..
no idea what the issue is but need to do a rebuild by the looks..
cheers!

[secondmouse]

I suspect it's not the problem of the kernel. I think it has something to do with the default shell on your work computer. If I'm not mistaken, it is either:
1. a line #!/bin/csh at the beginning of the script in question,
2. the default shell is csh on the work computer [ use echo $SHELL to find out ]and the shebang line #!/bin/bash is missing.

To replicate the problem, change the shebang line on the scripts listed on this page so far to #!/bin/csh and run the script in this way: (script needs to be made executable first)

./script

I think it's a good habit to specify which shell you will be using in the script otherwise problems like this will surface.

Reference: if: Expression Syntax. Blog of Annoying Technical Details

[cayalee]

thankyou very much for this, most usefull!