Shell脚本中的布尔表达式

Question

将以下内容作为布尔表达式的"正确"方法是什么？

for i in `ls $1/resources`; do
    if [ $i != "database.db" ]
    then
        if [ $i != "tiles" ]
        then
            if [ $i != "map.pdf" ]
            then
                if [ $i != "map.png" ]
                then
                    svn export -q $1/resources/$i ../MyProject/Resources/$i
...

Answer 1

其他解决方案有几个常见的错误:http: //www.pixelbeat.org/programming/shell_script_mistakes.html

1. for i in $(ls ...) 是多余的/有问题的只是做: for i in $1/resources*; do ...

2. [ $i != file1 -a $1 != file2 ] 这实际上有两个问题.

   一个.在$i没有加引号,因此用空格会导致一些问题名

   湾 -a如果stat文件没有短路(我知道上面不是stat文件),效率很低.

所以请尝试:

for i in $1/resources/*; do
    if [ "$i" != "database.db" ] &&
       [ "$i" != "tiles" ] &&
       [ "$i" != "map.pdf" ] &&
       [ "$i" != "map.png" ]; then
        svn export -q "$i" "../MyProject/Resources/$(basename $i)"
    fi
done

Answer 2

更短:

for i in `ls $1/resources`; do
  if [ $i != databse.db -a $i != titles -a $i != map.pdf ]; then
    svn export -q $1/resources/$i ../MyProject/Resources/$i
  fi
done;

的-a在如果expression布尔AND壳式测试的等效.欲了解更多man test