Re: My bash script is missing something - what?

[Greg Wooledge <wooledg@eeg.ccf.org>]

On Mon, Oct 10, 2016 at 04:10:22PM +0200, Nicolas George wrote:
> Le nonidi 19 vendémiaire, an CCXXV, Greg Wooledge a écrit :
> > > That just fails differently by responding:
> > > 
> > > : No such file or directory
> > 
> > Carriage return.  Did you edit this script with a Microsoft Windows
> > program, perhaps?  The shebang line (#!/bin/bash) probably ends with
> > a carriage return + line feed, instead of just a line feed.
> 
> I had the same diagnosis. Note that modern shells print a more useful
> diagnosis:
> 
> execve("/tmp/foo.sh", ["/tmp/foo.sh"], [/* 45 vars */]) = -1 ENOENT (No such file or directory)
> open("/tmp/foo.sh", O_RDONLY|O_NOCTTY)  = 3
> read(3, "#!/bin/sh\r\n", 64)            = 11
> close(3)                                = 0
> ioctl(2, TCGETS, {B38400 opost isig icanon echo ...}) = 0
> write(2, "zsh:1: /tmp/foo.sh: bad interpreter: /bin/sh^M: no such file or directory\n", 74) = 74
> exit_group(127)                         = ?

Actually, I'm going to change my diagnosis slightly.  The shebang is fine,
but the "cat /etc/debian_version" line has a carriage return at the end.
The error message is coming from cat.

If the shebang is wrong, bash (as interactive shell) prints:

bash: ./foo: /bin/bash^M: bad interpreter: No such file or directory

which is very close to your zsh message.  But putting the carriage return
on the cat command gives:

wooledg@wooledg:~$ ./foo
: No such file or directory

which is really:

wooledg@wooledg:~$ ./foo 2>&1 | less
cat: /etc/debian_version^M: No such file or directory

How the original poster ended up with a script with an extra carriage
return on just *one* line, rather than every line, is a mystery to me.