我尝试执行以下命令：
su -l user1 -c "hive -e \"ALTER TABLE schema1.table1 DROP IF EXISTS PARTITION (att1=\"$val\");\""
我收到错误消息：
FAILED: ParseException line 1:81 cannot recognize input near 'val1' ')' '<EOF>' in constant
所以这里的问题是由于第二级嵌套的双引号引起的，在它们之间有一个变量$val，其值为val1。
您能帮我解决吗？最好的办法是给我一个嵌套引号的规则。
答案 0 :(得分：0)
In this particular case, you can use single quotes instead of the internal (currently escaped) double quotes, since single quotes inside double quotes are not special at all.
su -l user1 -c "hive -e 'ALTER TABLE schema1.table1 DROP IF EXISTS PARTITION (att1=\"$val\");'"
In the general case, you can't always avoid death by backslash escapes. The general quoting rules are very straightforward; text between single quotes is quoted verbatim, whereas double quotes are weaker but allow you to backslash things which should not be touched by the shell.