Question

I would like to automate the following svn command. Note this command produces the desired results on my system – Ubuntu 10.04, svn 1.6.6, bash shell, when issued from the command line:

svn ci -m $'Added new File: newFile.txt\nOrig loc: /etc/networking/newFile.txt' /home/user/svnDir/newFile.txt

I would like to run that command in a bash script, assuming that the original full path to the file is contained in the variable $oFileFull, and the filename is in $oFileName. The script is executed from the svn directory. I need to allow for the possibility that the file name and or path contain spaces.

so the line inside my shel script might look like:

svn ci -m$'Added new file: ${oFileName}\nOrig loc: ${oFileFull}' ${oFileName}

But I want the variables (which may contain spaces) expanded before the command is executed, and I cannot figure out how to do this while enclosing the svn comment in single quotes which is necessary in order to get the new line in the subversion comment log. I am pulling my hair out trying to figure out how to properly quote and assemble this command. Any help appreciated.

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• The following was posted as an answer, but should have been an edit.

@Dennis:

Wow, this is hard to wrap my head around, I’d love it if someone could point me towards an online resource that explains this clearly and concisely. The ones I have found have not cleared it up for me.

My latest source of confusion is the following:

#!/bin/bash
nl=$'\n'
msg="Line 1${nl}Line 2"
echo $msg        # ouput = Line 1 Line 2
echo -e $msg     # ouput = Line 1 Line 2
echo "$msg"      # output = Line 1
                 # Line 2

What I’m attempting to illustrate is that having the double quotes around the variable $msg splits the output into two lines, without the double quotes, even with the -e switch, there is no new line.

I don’t get why the double quotes are necessary – why isn’t the $nl variable expanded when it is assigned as part of the msg variable?

I hope I’m not committing a StackOverflow faux pas by answering my own question. And in fact, I am not really providing an answer, but merely a response to your comment. I cannot format a comment as necessary.

Answer 1

Put your newline in a variable, use the variable wherever you need a newline and change the quotes around your larger string to double quotes. You should also always quote any variable that contains a filename.

nl=$'\n'
svn ci -m"Added new file: ${oFileName}${nl}Orig loc: ${oFileFull}" "${oFileName}"