[ruby] irb 안에서 irb 사용하기

irb안에서 irb 사용이 가능하다.  즉 새로운 session을 만들 수 있고 종료할 수 있다. 

session 이동(session switching)은 fg #숫자 로 이동한다. 

my_string = "foo"

=> "foo"

>> foo = "foo"

=> "foo"

>> irb

>> foo

NameError: undefined local variable or method `foo' for main:Object

from (irb#1):1

>> jobs

=> #0->irb on main (#<Thread:0x007fd71b05b7d0>: stop)

#1->irb#1 on main (#<Thread:0x007fd71b1beeb0>: running)

>> fg 0

=> #<IRB::Irb: @context=#<IRB::Context:0x007fd71b0b57a8>, @signal_status=:IN_EVAL, @scanner=#<RubyLex:0x007fd71b0a8710>>

>> foo

=> "foo"

>> jobs

=> #0->irb on main (#<Thread:0x007fd71b05b7d0>: running)

#1->irb#1 on main (#<Thread:0x007fd71b1beeb0>: stop)

>> irb

>> jobs

=> #0->irb on main (#<Thread:0x007fd71b05b7d0>: stop)

#1->irb#1 on main (#<Thread:0x007fd71b1beeb0>: stop)

>> kill 1

=> [1]

>> jobs

=> #0->irb on main (#<Thread:0x007fd71b05b7d0>: stop)

#2->irb#2 on main (#<Thread:0x007fd71b0f9048>: running)