shell在单个if条件中编写多个条件的脚本

Question

In the code below, in /bin/sh, why is second condition of -o evaluated when first condition is satisfied. The scenario is that $output has multiple "ORA-" strings in separate lines, but it doesnot have "INVALID_OBJECTS" string. So first part is true, but second part becomes

"" -gt 0

which fails with

sh: [: missing `]'

if [ "`echo "$output" | grep ORA-`" -o "`echo "$output" | awk '/INVALID_OBJECTS/{getline;getline;print $0}' | sed 's/\s//g'`" -gt 0 ]; then
        echo -e "\n*** ERROR:  ***\n"
fi

UPDATE: The $output holds stdout of pl-sql block. The end-user had entered Ctrl+C during execution of the pl-sql block, which resulted in loss of connection to SQL* Plus. So the stdout ended up having multiple "ORA-nnnnn" errors. If there was no loss of connection, I would have got the following lines in $output which is checked in left side of the -o check.

INVALID_OBJECTS  
_ _ _ _ _ _ _ _ _ _  
                   3

Answer 1

Well, let's simplify your expression first a bit, by removing unnecessary quotes. The test command basically boils down to:

[ `echo $output | grep ORA-` -o `echo $output | awk '/INVALID_OBJECTS/{getline;getline;print $0}' | sed 's/\s//g'` ]

So you have basically zero or more words (depending on what the grep yields) on the left of the -o , followed by zero or one word (depending on what awk yields) to the right of the -o .

Now I have no idea WHAT you want to achieve here, but you can see from this analysis, that your command does not make sense.