Question

我有一些bash代码，它似乎无法运作，我无法弄清楚原因。 if语句有问题，但我无法理解它。

function param_err_non {
        echo "error: parameter missing"
        return 1
}

function param_err_many {
        echo "error: too many parameters"
        return 1
}

function param_err_invl {
        echo "error: invalid parameter"
        return 1
}

dbcmd=""
dbusr=""
dbste="" #this isn't so obvious, it's the site name
dbkey=""
dbval=""
nopar=0

if [ "$1" = "" ]; then param_err_non; fi

case "$1" in
        get)
                dbcmd=$1
                ;;                                                                                      
        put)                                                                                            
                dbcmd=$1                                                                                
                ;;                                                                                      
        del)                                                                                            
                dbcmd=$1                                                                                
                ;;                                                                                      
        new)                                                                                            
                dbcmd=$1                                                                                
                ;;                                                                                      
        list)                                                                                           
                dbcmd=$1                                                                                
                nopar=1                                                                                 
                ;;
        *)
                param_err_invl
esac

echo "running command $dbcmd"

if [ "$dbcmd" = "" ]; then param_err_non; fi

if [ "$2" = "" ]; then param_err_non; else dbusr=$2; fi

if [ $nopar -eq 0 ]; then
        if [ "$3" = "" ]; then param_err_non; else dbste=$3; fi
fi

counter=
for param in "$@"
do

        let counter=counter+1

        if [ "$dbcmd" = "del" ]; then
                echo "entering delete param check $counter"
                if [ "$3" = "" ]; then deleteall=1; else
                         if [ $counter -eq 4 ]; then param_err_many; fi
                fi
        fi

        if [ "$dbcmd" = "get" ]; then
                if [ $counter -eq 4 ]; then dbkey="$4"; fi
                if [ $counter -ge 5 ]; then param_err_many; fi
        fi

        if [ "$dbcmd" = "put" ]; then
                if [ $counter -eq 4 ]; then dbkey="$4"; fi
                if [ $counter -eq 5 ]; then dbval="$5"; fi
                if [ $counter -ge 6 ]; then param_err_many; fi
        fi

        if [ "$dbcmd" = "new" ]; then
                if [ $counter -eq 4 ]; then param_err_many; fi
        fi

        if [ "$dbcmd" = "list" ]; then
                if [ $counter -eq 4 ]; then param_err_many; fi
        fi
done

我得到的输出如下......

$ source db-scripts/sitedb.bash del john thirdtest
running command del
entering delete param check 1
entering delete param check 2
entering delete param check 3
bash: [: =: unary operator expected
error: parameter missing

我真的只需要额外的一双眼睛，因为有问题的if语句似乎都很好。

Answer 1

问题是类似于以下几行的问题之一：

if [ $counter -eq 4 ]; then param_err_many; fi

修复方法是将变量括在双引号中 - "$counter"，或者将计数器初始化为0而不是空字符串。

如果这不能解决问题，那么您应该在问题中出现错误的位置附近运行bash -x yourscript.sh的调试输出。事实上，在将来，如果shell中出现异常，首先要做的是使用bash -x运行它以查看出现了什么问题。

bash一元运算符的预期，if语句看不出任何错误

1 个答案: