Linux的bash腳本：使用轉義字符的字符串，如果比較

Question

代碼：

if [["$MP" -ne "$vl2"]]; then 
    echo -e "Comparing Apples to Oranges !!\n" >> ${LOGFILE} 
    subject="$0 : Warning : Please check Source Directory" 
    SendEmail I "${subject}" "" "${LOGFILE}" "${vel}" 
    exit 99 
fi 

這裏是輸出：請檢查最後一行的錯誤。謝謝 ！

+ PG=./cleanupADir.sh 
+ MP=/u01/oracle 
+ TH=90 
+ MT=3 
+ TY=log 
+ SD=/u01/oradata/logs 
++ expr length /u01/oracle 
+ vl1=11 
++ expr substr /u01/oradata/logs 1 11 
+ vl2=/u01/oradat 
+ echo /u01/oradat /u01/oracle 
/u01/oradat /u01/oracle 
+ '[[/u01/oracle' -ne '/u01/oradat]]' 
./cleanupADir.sh: line 73: [[/u01/oracle: No such file or directory 

Answer 1

添加幾個空格[[之後和之前]]，以及串改變ne到!=：

if [[ "$MP" != "$vl2" ]]; then 

類似的會議：

$ set -x 
$ export x=apple 
+ export x=apple 
+ x=apple 
$ export y=orange 
+ export y=orange 
+ y=orange 
$ if [["$x" -ne "$y"]];then echo "XXX";fi 
+ '[[apple' -ne 'orange]]' 
bash: [[apple: command not found 
if [[ "$x" -ne "$y" ]];then echo "XXX";fi 
+ [[ apple -ne orange ]] 
if [[ "$x" != "$y" ]];then echo "XXX";fi 
+ [[ apple != \o\r\a\n\g\e ]] 
+ echo XXX 
XXX