Linux Bash腳本：if中的字符串與轉義字符的比較

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

輸出為：請檢查最后一行的錯誤。 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

添加幾個空格后的[[和之前的]] ，和字符串改變ne來!= ：

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

一個類似的會話：

$ 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