Yeah, thought the expansion might be causing the issue. Thanks, Greg Borbonus
On Sat, Sep 5, 2020, 10:44 AM Eliot Moss <m...@cs.umass.edu> wrote: > On 9/5/2020 11:29 AM, Greg Borbonus via Cygwin wrote: > > Out of curiosity, why are there 2 different sets of quotes? > > > > Thanks, > > Greg Borbonus > > > > On Fri, Sep 4, 2020, 10:23 PM Bob McGowan via Cygwin <cygwin@cygwin.com > > > > wrote: > > > >> I am trying to set things up so the Bash profile detects if bash is > >> running from the Windows "XWin Server" startup link or not. The startup > >> link has the following as the command: > >> > >> C:\cygwin64\bin\run.exe --quote /usr/bin/bash.exe -l -c "cd; exec > >> /usr/bin/startxwin" > >> > >> So I thought I'd try adding the env command to set an environment > variable: > >> > >> C:\cygwin64\bin\run.exe --quote /usr/bin/env startxwin=yes > >> /usr/bin/bash.exe -l -c "cd; exec /usr/bin/startxwin" > >> > >> This works (if there's a better way, I'd be happy to learn of it) but > in > >> the process of testing I had a problem when echo'ing the variable. > >> > >> For purposes of describing the bug, I simplified the command as > follows: > >> > >> env startup=yes bash -l -c 'echo "cmd: $startup"' > >> > >> I also added an "echo profile: $startup" to the .bash_profile file. > >> > >> When I run the above in a Cygwin shell, the output is: > >> > >> $ env startup=yes bash -l -c "echo cmd: $startup" > >> profile: yes > >> $ > >> > >> When I run it in a Linux shell, the output is: > >> > >> $ env startup=yes bash -l -c 'echo "cmd: $startup"' > >> profile: yes > >> cmd: yes > >> $ > >> > >> As you can see, the Cygwin side fails to generate any output from the > -c > >> echo command but on the Linux system there is output. > >> > >> Normally I'd call this a bug but since this is running under Windows it > >> may be some weirdness of the implementation required to create the > Linux > >> like environment. > >> > >> The Bash version in Cygwin is 4.4.12(3)-release and for my Debian > Linux > >> system, it is 5.0.3(1)-release. So it could also be that it existed in > >> Linux 4.x series and has been fixed in the 5.x series. > > The inner quotes are necessary because there are two spaces beween cmd: and > $startup, and the : may be risky unquoted in bash (actually it is ok, but I > try to be careful about anything not a letter or digit, etc.). The outer > ones > are single quotes, which protect $startup from being expanded before it > gets > to the new bash. " " (double) quotes do not prevent $ expansion. (You > want > the new bash to do the expansion.) However, I think this would also work: > > env startup=yes bash -l -c echo 'cmd: $startup' > > Regards - Eliot Moss > -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
