I'm trying to find the return codes from bash for piped commands. i.e.
system("ls")
puts("#{$?.exitstatus}")
This returns the return code of ls
system("ls | bzip2 -c > ./out.txt")
how can I still get the return code of ls?
Thanks,
Russell.
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you cannot. this is a bash limitation.
if you need to do that use something like:
stdout = IO.popen('ls'){|pipe| pipe.read}
p $?.exitstatus
stdout = IO.popen('bzip2 -c', 'r+'){|pipe| pipe.write stdout; pipe.close_write; pipe.read}
p $?.exitstatus
On May 7, 2008, at 9:33 AM, Russell Quinn wrote:
how can I still get the return code of ls?
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we can deny everything, except that we have the possibility of being better. simply reflect on that.
h.h. the 14th dalai lama
system("ls | bzip2 -c > ./out.txt")
how can I still get the return code of ls?
If you're using bash then it has an shell variable that records the exit
status of all commands in a pipeline (it's an array). Do 'man bash'.
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Thanks for the reply. But there is a pipestatus array in bash isn't
there?
ls | foo
echo ${PIPESTATUS[0]}
see:
http://aplawrence.com/Blog/B955.html
I just couldn't get it to work from Ruby
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Russell Quinn wrote:
ls | foo
echo ${PIPESTATUS[0]}
I just couldn't get it to work from Ruby
try 'ls | echo; exit ${PIPESTATUS[0]}'
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that's because you've lost the bash process by the time bash exits. use my session gem if you want a persistent bash session against which to run commands:
require 'session'
bash = Session::Bash.new
stdout, stderr = bash.execute 'ls | grep something'
p bash.status
stdout, stderr = bash.execute 'echo ${PIPESTATUS[0]}'
p bash.status
etc. session uses a *single* bash session for all it's commands so you can do this sort of thing. however i'm not sure what the point is when pipelining from ruby, without shelling out, is so easy?
regards.
On May 7, 2008, at 9:50 AM, Russell Quinn wrote:
Thanks for the reply. But there is a pipestatus array in bash isn't
there?ls | foo
echo ${PIPESTATUS[0]}
I just couldn't get it to work from Ruby
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we can deny everything, except that we have the possibility of being better. simply reflect on that.
h.h. the 14th dalai lama
try 'ls | echo; exit ${PIPESTATUS[0]}'
Magical! thanks 
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