Logical operators (“and”, “or”) in DOS batch...펌

Logical operators (“and”, “or”) in DOS batch

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up vote115down votefavorite 26	How would you implement logical operators in DOS Batch files? shell dos batch-file share|improve this question edited Jan 26 '10 at 23:02 Dave Jarvis 13.5k2284182 asked Jan 26 '10 at 22:32 JoelFan 13.4k1984153
	5   I submit for your viewing pleasure: pi.bat :) thedailywtf.com/Articles/… –  Scott Anderson Jan 26 '10 at 22:47 1   wow... command-line-programming.suite101.com/article.cfm/… –  JoelFan Jan 28 '10 at 17:10 add a comment |

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You can do and with nested conditions: if %age% geq 2 ( if %age% leq 12 ( set class=child ) ) or: if %age% geq 2 if %age% leq 12 set class=child You can do or with a separate variable: set res=false if %hour% leq 6 set res=true if %hour% geq 22 set res=true if "%res%"=="true" ( set state=asleep ) share|improve this answer edited Aug 2 '10 at 6:33 answered Jan 26 '10 at 23:07 paxdiablo 413k967941242

6   You can also just use set res= or set res=1 and then if defined res which is a little more robust against typos and works even in blocks without explicitly enabling delayed expansion. –  Joey Jan 26 '10 at 23:34 3   Just to improve your answer a bit... you don't need to explicitly nest the "if" statements... you can just "chain" them, as Dave Jarvis demonstrates below –  JoelFan Jan 28 '10 at 14:44 add a comment |

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up vote34down vote	The MS-DOS IF statement does not support logical operators (AND and OR), cascading IF statements make an implicit conjunction. IF Exist File1.Dat IF Exist File2.Dat GOTO FILE12_EXIST_LABEL If File1.Dat and File1.Dat exist then jump the label FILE12_EXIST_LABEL. See also: IF /? share|improve this answer edited Jul 24 '14 at 16:28 answered Jan 26 '10 at 22:34 Dave Jarvis 13.5k2284182
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up vote23down vote

De Morgan's laws allow us to convert disjunctions ("OR") into logical equivalents using only conjunctions ("AND") and negations ("NOT"). This means we can chain disjunctions ("OR") on to one line. This means if name is "Yakko" or "Wakko" or "Dot", then echo "Warner brother or sister". set warner=true if not "%name%"=="Yakko" if not "%name%"=="Wakko" if not "%name%"=="Dot" set warner=false if "%warner%"=="true" echo Warner brother or sister This is another version of paxdiablo's "OR" example, but the conditions are chained on to one line. (Note that the opposite of leq is gtr, and the opposite of geq is lss.) set res=true if %hour% gtr 6 if %hour% lss 22 set res=false if "%res%"=="true" set state=asleep