bash bash

kornelix · 05-29-2006, 04:07 AM

After an hour of scratching my head, I discovered the following:

In a bash script, if a command is split on two lines like this:

Code:

cp /home/name/dirk/file1 \  <-- (extra space after backslash)
   /tmp/xxx/file2

Bash will not put the lines together, so the command fails and line 2 is attempted as a new command.

Is this as dumb as it appears?
Or is it me?

druuna · 05-29-2006, 04:17 AM

Hi,

The command given is incorrect, the extra space behind the backslash should not be there if you want the command to continue on the next line.

From the man page:

Quote:

A non-quoted backslash (\) is the escape character. It preserves the
literal value of the next character that follows, with the exception of
<newline>. If a \<newline> pair appears, and the backslash is not
itself quoted, the \<newline> is treated as a line continuation (that
is, it is removed from the input stream and effectively ignored).

To tell bash to continue the command on the next line, you need a backslash followed immediately by a new-line.

Works as designed

Hope this clears things up a bit.

kornelix · 05-29-2006, 05:21 AM

Thanks. Upon reflection, seems reasonable.

I had forgotten that backslash has two purposes: "escape next character" and "continue on next line".

Hko · 05-29-2006, 06:10 AM

Quote:

Originally Posted by kornelix

I had forgotten that backslash has two purposes: "escape next character" and "continue on next line".

IMO Your problem actually was that the backslash has only one purpose: a backslash inmediately followed by a newline-character ('\n') really is an escaped newline-character.

kornelix · 05-29-2006, 12:44 PM

Got it. thanks again.