Re: [MLUG] backup via cron

[Mike Miller <EMAIL:PROTECTED>]

On Sat, 4 Feb 2006, Stephen Montgomery-Smith wrote:

> My theory was wrong.  I don't know why the semi-colon fixed the script. 
> Maybe it is a bug with bash.

I doubt that your theory was completely wrong.  He might have deleted the 
carriage return inadvertently (they are invisible in nano).  It is 
possible that some other invisible character was there.  This kind of 
thing comes up a lot with my students.  I was once stumped on a problem 
and found out with the help of one of our supercomputer staff that one 
character in my script was something weird.  I don't know where it came 
from.  Many programs will show some characters as spaces when they are not 
space characters.  Here are two things I've sometimes done when I can't 
figure out what's wrong:

less -u filename

tr -d '[ -~]\n' < filename | wc

The less command will reveal the carriage returns as ^M characters 
highlighted in reverse video.

The tr command deletes all characters not in the normal ascii set.  The tr 
command followed by wc should return all zeros like this:

# tr -d '[ -~]\n' < .cshrc | wc
       0       0       0

If it does not return all zeros, there's something in the file such as a 
control character or other weirdness.  You can redirect the output of tr 
to a file and examine what you have:

# tr -d '[ -~]\n' < filename > test_file_to_examine.out

Once you figure out what the characters are, you can go back to your 
original file and try to repair it.

Mike

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