# \[feature:1.9\] ENV#\[\]= and nil

**URL:** <https://www.ruby-forum.com/t/feature-1-9-env-and-nil/149197>\
**Category:** Development\
**Created:** [September 22, 2008, 1:51pm UTC](https://www.ruby-forum.com/t/feature-1-9-env-and-nil/149197 "2008-09-22T13:51:17Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Yusuke\_ENDOH](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c89c15/32.png) [@Yusuke\_ENDOH](https://www.ruby-forum.com/u/Yusuke_ENDOH)\
**Post date:** [September 22, 2008, 1:51pm UTC](https://www.ruby-forum.com/t/feature-1-9-env-and-nil/149197/1 "2008-09-22T13:51:17Z")

</div>

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1.8 e$B$G$Oe(B ENV[“FOO”] = nil e$B$O4D6-JQ?t$r\>C$7$^$9$,!"e(B1.9  
e$B$G$O%(%i!\<$K$J$j!"e(B  
e$BITJX$G$9!#;R%W%m%;%9$r:n$k$H$-$J$I$G!"0l;~E\*$K4D6-JQ?t$rJQ$($k$?$a$Ke(B

```
env_foo = ENV["FOO"]
ENV["FOO"] = "something"
system(...)
ENV["FOO"] = env_foo

```

e$B$G:Q$s$G$$$?$H$3$m$,e(B

```
env_foo = ENV["FOO"]
ENV["FOO"] = "something"
system(...)
if env_foo
  ENV["FOO"] = env_foo
else
  ENV.delete("FOO")
end

```

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e$B!Ve(Bnil  
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1. 1.8 e$B$N5sF0$KLa$9e(B (ENV e$B$@$1e(B nil e$B$rFCJL07$$$9$ke(B)
2. 1.8 e$B$Ne(B ENV#[]= e$B$HF1$85sF0$r$9$k%a%=%C%I$rDs6!$9$ke(B  
(ENV#assign e$B$H$+e(B)

e$B$N$I$C$A$+$r$9$k$N$O$I$&$G$7$g$&$+!#e(B

---

<div class="post-metadata">

**Author:** ![Yusuke\_ENDOH](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c89c15/32.png) [@Yusuke\_ENDOH](https://www.ruby-forum.com/u/Yusuke_ENDOH)\
**Post date:** [September 23, 2008, 1:30am UTC](https://www.ruby-forum.com/t/feature-1-9-env-and-nil/149197/2 "2008-09-23T01:30:14Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:36465] [feature:1.9] ENV#[]= and nil”  
on Mon, 22 Sep 2008 20:42:38 +0900, “Yusuke ENDOH” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:  
|1.8 e$B$G$Oe(B ENV[“FOO”] = nil e$B$O4D6-JQ?t$r\>C$7$^$9$,!"e(B1.9 e$B$G$O%(%i!\<$K$J$j!"e(B  
|e$BITJX$G$9!#;R%W%m%;%9$r:n$k$H$-$J$I$G!"0l;~E\*$K4D6-JQ?t$rJQ$($k$?$a$Ke(B

\<e$BCfN,e(B\>

|e$B$H$H$F$b\>iD9$K$J$j$^$9!#$$$m$s$J%=!\<%9$G$3$N%3!\<%I$r=q$/I,MW$,$"$j$^$9!#e(B  
|e$B!Ve(Bnil e$B$NFCJL07$$$r$J$/$9!W$H$$$&0l4S@-$N$?$a$K!"MxJX@-$,5\>@7$K$J$j$9$.e(B  
|e$B$@$H;W$$$^$9!#e(B  
|  
|e$B$J$N$G!"e(B  
|  
|1. 1.8 e$B$N5sF0$KLa$9e(B (ENV e$B$@$1e(B nil e$B$rFCJL07$$$9$ke(B)  
|2. 1.8 e$B$Ne(B ENV#[]= e$B$HF1$85sF0$r$9$k%a%=%C%I$rDs6!$9$ke(B (ENV#assign e$B$H$+e(B)  
|  
|e$B$N$I$C$A$+$r$9$k$N$O$I$&$G$7$g$&$+!#e(B

e$B$\*$C$7$c$k$3$H$O$b$C$H$b$J$N$GA0\<T$NBP1~$r$7$^$9!#e(B

---

<div class="post-metadata">

**Author:** ![Yusuke\_ENDOH](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c89c15/32.png) [@Yusuke\_ENDOH](https://www.ruby-forum.com/u/Yusuke_ENDOH)\
**Post date:** [September 23, 2008, 1:37am UTC](https://www.ruby-forum.com/t/feature-1-9-env-and-nil/149197/3 "2008-09-23T01:37:50Z")

</div>

e$B%A%1%C%He(B #584 e$B$,99?7$5$l$^$7$?!#e(B (by Yukihiro M.)

e$B%9%F!\<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B  
e$B?JD=e(B % 0e$B$+$ie(B100e$B$KJQ99e(B

## Applied in changeset r19463.

[http://redmine.ruby-lang.org/issues/show/584](http://redmine.ruby-lang.org/issues/show/584)