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Validate a program exist,we should avoid "which" Refer to http://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script/677212#677212 TrivialFix Change-Id: I3d614aef2ac6598a51d830b02795ef186d4fc531
Validate a program exist,we should avoid "which" Refer to http://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script/677212#677212 TrivialFix Change-Id: I3d614aef2ac6598a51d830b02795ef186d4fc531