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Which Ruby shell uses as its subshell?

If i do

`echo $SHELL`

I get /bin/bash.

But if I try to run this loop:

`for x in {1..20}; do echo $x; done`

I get {1..20}instead of the expected 20 numbers.

Maybe ruby ​​uses a different shell to run these commands? How can I get around this?

EDIT: Software Version:

$ irb --version
irb 0.9.5(05/04/13)
$ ruby --version
ruby 1.8.7 (2010-06-23 patchlevel 299) [x86_64-linux]
$ bash --version
GNU bash, version 4.1.5(1)-release (x86_64-pc-linux-gnu)
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1 answer

Ruby uses shas a subshell for backticks and #system. $SHELL- this is your default shell, $0should tell you the current shell. You can get the desired shell by calling it specially

$ ruby -v
ruby 1.8.7 (2011-02-18 patchlevel 334) [x86_64-linux], MBARI 0x6770, Ruby Enterprise Edition 2011.03
$ irb --version
irb 0.9.5(05/04/13)
$ irb
irb(main):001:0> `echo $0 -- $SHELL`
=> "sh -- /bin/bash\n"
irb(main):002:0> `bash -c 'echo $0 -- $SHELL'`
=> "bash -- /bin/bash\n"
irb(main):003:0> ENV['SHELL']
=> "/bin/bash"
irb(main):004:0> system 'bash', '-c', 'echo $0 -- $SHELL'
bash -- /bin/bash
=> true
irb(main):005:0> system 'echo $0 -- $SHELL'
sh -- /bin/bash
=> true
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