Shell script error: "[: =: unary operator expected"

Shell script error: "[: =: unary operator expected"

Md5_109a = "81ab961153b62d207f0f517048881b5d"
Md5_1_ B = 'md5sum install. Bin | awk '{print $1 }''
If [$ md5_109a! = $ Md5_1_ B]

Cause: when the file install. Bin does not exist, $ md5_1_ B is empty so that the comparison string becomes

If [81ab961153b62d207f0f517048881b5d! =] The statement is invalid.

Can be changed

If [[$ md5_109a! = $ Md5_1_ B]

Or if ["$ md5_109a"! = "$ Md5_1_ B" A]

Problem Solving

This article is from the "tonylinux" blog, please be sure to keep this source http://tonylinux.blog.51cto.com/2268300/1441515

Shell script error: "[: =: unary operator expected"