pythonbrew bashrc awk line no longer works

Question

I recently upgraded my FreeBSD box and now pythonbrew seems to be broken. It bails out of the .pythonbrew/etc/bashrc file on this line:

PATH_WITHOUT_PYTHONBREW=$(printf "$PATH" | awk -v RS=: -v ORS=: "/${PATH_ROOT//\//\/}/ {next} {print}" | sed -e 's#:$##')

Gives the error:

awk: syntax error at source line 1
   context is
      >>> //home/myusername/. <<< pythonbrew/ {next} {print}
awk: bailing out at source line 1

That PATH_ROOT variable is

/home/myusername/.pythonbrew

It seem for me that you try to read variable inside `awk` code. Use `awk` like this `awk -v RS=: -v ORS=: -v path=$path_root '$0==path {next...` — Jotne, Mar 31 '14 at 18:15
Does `${PATH_ROOT//\//\\\/}` work? Though as @Jotne suggests using `-v` is likely a better plan. Though with `$0 ~ path` if you want the regex match and not equality. — Etan Reisner, Mar 31 '14 at 18:25

Ed Morton · Accepted Answer · 2014-04-01T16:45:22.110

Don't put variables in your printf formatting argument as that'll fail when your variable contains printf formatting charcters, e.g. '%'. So use printf "%s" "$PATH" instead of printf "$PATH".
It is never a good idea to use double quotes to delimit an awk script as it introduces double quoting hell in the rest of the script. So use '/'"${PATH_ROOT//\//\/}"'/{...}' instead of "/${PATH_ROOT//\//\/}/{...}"
It is almost never a good idea to allow shell variable expansion to provide parts of the body of your awk script dynamically as it introduces the potential for bizarre syntax errors. So use awk -v path_root="${PATH_ROOT//\//\/}" '$0 ~ path_root{...}' instead of '/'"${PATH_ROOT//\//\/}"'/{...}'.
Rather than test for a condition and use next and then use a print if the condition isn't present, you can just test for the negation of the condition.
When setting 2 variables to the same value (e.g. RS and ORS), it's clearest to set them together rather than separately.

So, all together, as a starting point your script would be:

PATH_WITHOUT_PYTHONBREW=$(printf "%s" "$PATH" |
    awk -v path_root="${PATH_ROOT//\//\/}" 'BEGIN{RS=ORS=":"} $0 !~ path_root' |
    sed -e 's#:$##')

assuming your PATH_ROOT manipulation makes sense.

It could be further improved but that should be enough to get rid of your error.

Awesome, thank you! There is an extra single quote in there in front of $0 that I can't remove as it wants the edits to be at least 6 characters, but once that is removed it works great. I'll see about adding this as a patch to pythonbrew as well. — CaptainThrowup, Apr 01 '14 at 14:38
You're welcome and I updated my script to remove that single quote. If you'd like to update your question with some samples of what "PATH" can contain and what you'd want "PATH_WITHOUT_PYTHONBREW" to be set to given those PATH settings, I'm sure we could show you how to do it trivially in a single awk command rather than invoking multiple commands and pipes. — Ed Morton, Apr 01 '14 at 16:48

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