unary operator expected

Shell foot This report wrong: "[: =: unary operator expected"When matching strings are equal, I use a statement like this:if [$STATUS = = "OK"]; Thenecho "OK"FiAt run time appeared [: =: unary operator expected error, has been unable to find the

Problem: Write the script execution when an error occurs, as follows650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M02/87/08/wKioL1fSHw_BhTzfAAAyENpN0rw591.png "title=" Sogou 20160909103121.png "alt=" Wkiol1fshw_bhtzfaaayenpn0rw591.png

I 've been learning Perl, and shell has forgotten about it. Today I wrote a small script to determine the operation when the second variable of the script is not equal to a certain string. If [$? -EQ 0] & [$2! = "WP"] Then : # Omitted Fi If the

When executing shell script, if judgment statement error#!/bin/bashif [0 = = $testNum]then echo "Check result:0" fi　　Testnum is not defined when used, no assignment is empty (originally defined, just a clerical error is similar to tsetnum), after

An expression C + + provides a rich operator and defines what these operators mean when the operands are of a built-in type. In addition, C + + supports operator overloading, allowing programmers to customize the meaning of the operator when used

When the centos system is switched from the root user to Oracle, the following message is always displayed:-Bash-: [: unary operator expectedIf the switchover succeeds, the above message is displayed. Later, the reason is found. When installing the

Operator Overloading in the Swift tutorial and swift Operator Overloading Http://www.raywenderlich.com/80818/operator-overloading-in-swift-tutorial Author: Corinne Krych Translator: Meng xiangyue blog: http://blog.csdn.net/mengxiangyue This is my

Operator Overloading in Swift tutorial Http://www.raywenderlich.com/80818/operator-overloading-in-swift-tutorial Author: Corinne Krych Translator: Meng xiangyue blog: http://blog.csdn.net/mengxiangyue This is my first translation. It is inevitable

http://blog.csdn.net/mengxiangyue/article/details/43437797Original address: Http://www.raywenderlich.com/80818/operator-overloading-in-swift-tutorial Corinne krych Translator: Mengxiang Month blog:http:// Blog.csdn.net/mengxiangyueThis article is my

The assignment operator is also used together with the arithmetic operator. It is mentioned in the appendix earlier. For example, to add x to 4 and then assign the value to x, you can write it as x + = 4. Copy codeThe Code is as follows: public