我想检查file2.sh是否存在，如果一个特定的单词，诗人是文件的一部分。我使用grep创建变量used_var。
#!/bin/ksh file_name=/home/file2.sh used_var=`grep "poet" $file_name`
如何检查used_var是否具有某些值？
而不是将grep的输出存储在变量中，然后检查变量是否为空，您可以这样做：
if grep -q "poet" $file_name
then
echo "poet was found in $file_name"
fi
============
以下是一些常用的测试：
-d FILE
FILE exists and is a directory
-e FILE
FILE exists
-f FILE
FILE exists and is a regular file
-h FILE
FILE exists and is a symbolic link (same as -L)
-r FILE
FILE exists and is readable
-s FILE
FILE exists and has a size greater than zero
-w FILE
FILE exists and is writable
-x FILE
FILE exists and is executable
-z STRING
the length of STRING is zero
例：
if [ -e "$file_name" ] && [ ! -z "$used_var" ]
then
echo "$file_name exists and $used_var is not empty"
fi
