I’m learning Python now, and imagine my future attempts at utilities like this will be done with it instead.

But I still think bash is awesome!

${inpt:${#inpt}-1}

This expands into the last character of inpt using only one parameter expansion. As a bonus (?), it makes the code almost as unreadable as Perl. :)

I have a book on sed and awk on my desk at work and wish I had more time to work through it so I might get these ideas in advance. I also wish I had spent the last 10 years learning this stuff instead of wasting my time in Windows. :-)

I figure it’s still good to struggle and figure it out one way or another, and try not to be paralyzed at the thought of all the better, quicker ways something might be done. I think I gained a little better understanding of how the pipeline works by figuring out how to use “read” in the bash script.

Anyway, I appreciate you taking the time to explain alternate options. I always want to understand my options better and pick the most suitable approach.


svn list -R file:///home/scarpent/src/svn |awk -F/ '$NF ~ /^$/ && NF <= 2'


awk is kind of like perl-lite. It is useful for parsing lines into fields at a separator. In this example, “/” is the separator. awk places the stuff between the separators into fields, which are addressable as $1, $2, etc. The number of fields is in the variable NF, and the contents of the last field are in $NF.

So, the awk statement parses the line (record in awk parlance) into fields at “/”, then for records that have no contents in the last field (i.e. the ones with a trailing “/”), and have a number of fields less than or equal to 2, print the line. The print is implied.

If you want to vary the number of fields to match, you can pass variables into awk using the -v switch:


svn list -R file:///home/scarpent/src/svn |awk -v NUM=2 -F/ '$NF ~ /^$/ && NF <= NUM'

which might make it more suitable for putting into a shell script.