bash 在 if else 语句中嵌套 for 循环
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Nesting a for loop in an if else statement
提问by Mechaflash
if [ ! -f ./* ]; then
for files in $(find . -maxdepth 1 -type f); do
echo $files
else
echo Nothing here
fi
Returns
退货
syntax error near unexpected token `else'
意外标记“else”附近的语法错误
New to this. Can anyone point me to what I did wrong?
新来的。谁能指出我做错了什么？
回答by Mischa Arefiev
You forgot done!
你忘了done！
if [ ! -f ./* ]; then
for files in $(find . -maxdepth 1 -type f); do
echo $files
done
else
echo Nothing here
fi
回答by jordanm
The reason you get a syntax error is because you are not ending the loop with the "done" statement. You should be using a while loop, instead of a for loop in this case, as the for loop will break if any of the filenames contain spaces or newlines.
出现语法错误的原因是您没有以“done”语句结束循环。在这种情况下，您应该使用 while 循环，而不是 for 循环，因为如果任何文件名包含空格或换行符，for 循环就会中断。
Also, the test command you have issued will also give a syntax error if the glob expands to multiple files.
此外，如果 glob 扩展为多个文件，您发出的测试命令也会出现语法错误。
$ [ ! -f ./* ]
bash: [: too many arguments
Here is a better way to check if the directory contains any files:
这是检查目录是否包含任何文件的更好方法：
files=(./*) # populate an array with file or directory names
hasfile=false
for file in "${files[@]}"; do
if [[ -f $file ]]; then
hasfile=true
break
fi
done
if $hasfile; then
while read -r file; do
echo "$file"
done < <(find . -maxdepth 1 -type f)
fi
Also, you could simply replace the while loop with find -print if you have GNU find:
此外，如果您有 GNU find，您可以简单地用 find -print 替换 while 循环：
if $hasfile; then
find . -maxdepth 1 -type f -print
fi
回答by Roger Lindsj?
The syntax for "for" is
“for”的语法是
for: for NAME [in WORDS ... ;] do COMMANDS; done
for: for NAME [in WORDS ... ;] do COMMANDS; 完毕
You are missing the "done"
你错过了“完成”
Try
尝试
if [ ! -f ./* ]; then
for files in $(find . -maxdepth 1 -type f); do
echo $files
done
else
echo Nothing here
fi
BTW, did you mean echo with lowercase rather than ECHO?
顺便说一句，你的意思是用小写而不是 ECHO 回声？
