如何使用php在字符串中用双反斜杠'\\'替换特殊字符反斜杠'\'？

this is my sample string

$str = "The ADE/Op's.(\\localhost\corporateoffice\COMMERCIAL\EODB Feedback\EODBfeedbacklist.xls) are contacted personally and see that positive feedback  "

Try like this,

$var=str_replace('\\','\\\\',$str);
 echo $var;

Double backslash are to escape the character