bash 收到“不明确的重定向”错误

Getting an "ambiguous redirect" error

提问by Open the way

The following line in my Bash script

我的 Bash 脚本中的以下行

 echo $AAAA"     "$DDDD"         "$MOL_TAG  >>  ${OUPUT_RESULTS}

gives me this error:

给我这个错误：

 line 46: ${OUPUT_RESULTS}: ambiguous redirect

Why?

为什么？

回答by nobar

Bash can be pretty obtuse sometimes.

Bash 有时可能非常迟钝。

The following commands all return different error messages for basically the same error:

以下命令都针对基本相同的错误返回不同的错误消息：

$ echo hello >
bash: syntax error near unexpected token `newline`

$ echo hello > ${NONEXISTENT}
bash: ${NONEXISTENT}: ambiguous redirect

$ echo hello > "${NONEXISTENT}"
bash: : No such file or directory

Adding quotes around the variable seems to be a good way to deal with the "ambiguous redirect" message: You tend to get a better message when you've made a typing mistake -- and when the error is due to spaces in the filename, using quotes is the fix.

在变量周围添加引号似乎是处理“模糊重定向”消息的好方法：当您输入错误时，您往往会得到更好的消息——并且当错误是由于文件名中的空格引起时，使用引号是解决办法。

回答by JUST MY correct OPINION

Do you have a variable named OUPUT_RESULTSor is it the more likely OUTPUT_RESULTS?

你有一个命名的变量OUPUT_RESULTS还是更有可能OUTPUT_RESULTS？

---

---

michael@isolde:~/junk$ ABC=junk.txt
michael@isolde:~/junk$ echo "Booger" > $ABC
michael@isolde:~/junk$ echo "Booger" >> $ABB
bash: $ABB: ambiguous redirect
michael@isolde:~/junk$ 

回答by ghostdog74

put quotes around your variable. If it happens to have spaces, it will give you "ambiguous redirect" as well. also check your spelling

在你的变量周围加上引号。如果它碰巧有空格，它也会给你“模糊重定向”。还要检查你的拼写

echo $AAAA"     "$DDDD"         "$MOL_TAG  >>  "${OUPUT_RESULTS}"

eg of ambiguous redirect

例如不明确的重定向

$ var="file with spaces"
$ echo $AAAA"     "$DDDD"         "$MOL_TAG >> ${var}
bash: ${var}: ambiguous redirect
$ echo $AAAA"     "$DDDD"         "$MOL_TAG >> "${var}"
$ cat file\ with\ spaces
aaaa     dddd         mol_tag

回答by Thomas

Does the path specified in ${OUPUT_RESULTS} contain any whitespace characters? If so, you may want to consider using ... >> "${OUPUT_RESULTS}"(using quotes).

${OUTPUT_RESULTS} 中指定的路径是否包含任何空白字符？如果是这样，您可能需要考虑使用... >> "${OUPUT_RESULTS}"（使用引号）。

(You may also want to consider renaming your variable to ${OUTPUT_RESULTS})

（您可能还想考虑将变量重命名为${OUTPUT_RESULTS}）

回答by AixNPanes

I've recently found that blanks in the name of the redirect file will cause the "ambiguous redirect" message.

我最近发现重定向文件名称中的空格会导致“不明确的重定向”消息。

For example if you redirect to application$(date +%Y%m%d%k%M%S).logand you specify the wrong formatting characters, the redirect will fail before 10 AM for example. If however, you used application$(date +%Y%m%d%H%M%S).logit would succeed. This is because the %kformat yields ' 9'for 9AM where %Hyields '09'for 9AM.

例如，如果您重定向到application$(date +%Y%m%d%k%M%S).log并指定了错误的格式字符，则重定向将在上午 10 点之前失败，例如。但是，如果你使用application$(date +%Y%m%d%H%M%S).log它就会成功。这是因为%k格式产量' 9'为上午9时，其中%H产量'09'为上午9时。

echo $(date +%Y%m%d%k%M%S)gives 20140626 95138

echo $(date +%Y%m%d%k%M%S)给 20140626 95138

echo $(date +%Y%m%d%H%M%S)gives 20140626095138

echo $(date +%Y%m%d%H%M%S)给 20140626095138

The erroneous date might give something like:

错误的日期可能是这样的：

echo "a" > myapp20140626 95138.log

where the following is what would be desired:

以下是所需的内容：

echo "a" > myapp20140626095138.log

回答by Jim

One other thing that can cause "ambiguous redirect" is \t\n\rin the variable name you are writing too

可能导致“模糊重定向”的另一件事是\t\n\r您正在编写的变量名称

Maybe not \n\r? But err on the side of caution

也许不是\n\r？但请谨慎行事

Try this

尝试这个

echo "a" > ${output_name//[$'\t\n\r']}

I got hit with this one while parsing HTML, Tabs \tat the beginning of the line.

我在解析 HTML 时遇到了这个问题，行首的 Tabs \t。

回答by Wayne Workman

I just had this error in a bash script. The issue was an accidental \ at the end of the previous line that was giving an error.

我刚刚在 bash 脚本中遇到了这个错误。问题是在上一行的末尾意外出现了一个 \ ，它给出了错误。

回答by enharmonic

If your script's redirect contains a variable, and the script body defines that variable in a section enclosed by parenthesis, you will get the "ambiguous redirect" error. Here's a reproducible example:

如果您的脚本的重定向包含一个变量，并且脚本主体在括号括起来的部分中定义了该变量，您将收到“模糊重定向”错误。这是一个可重现的示例：

1. vim a.shto create the script
2. edit script to contain (logit="/home/ubuntu/test.log" && echo "a") >> ${logit}
3. chmod +x a.shto make it executable
4. a.sh

1. vim a.sh创建脚本
2. 编辑脚本以包含 (logit="/home/ubuntu/test.log" && echo "a") >> ${logit}
3. chmod +x a.sh使其可执行
4. a.sh

If you do this, you will get "/home/ubuntu/a.sh: line 1: $logit: ambiguous redirect". This is because

如果你这样做，你会得到“/home/ubuntu/a.sh: line 1: $logit: ambiguous redirect”。这是因为

"Placing a list of commands between parentheses causes a subshell to be created, and each of the commands in list to be executed in that subshell, without removing non-exported variables. Since the list is executed in a subshell, variable assignments do not remain in effect after the subshell completes."

“在括号之间放置一个命令列表会导致创建一个子shell，并且列表中的每个命令都将在该子shell中执行，而不删除未导出的变量。由于列表是在子shell中执行的，因此不会保留变量分配在子shell完成后生效。”

From Using parenthesis to group and expand expressions

从使用括号对表达式进行分组和展开

To correct this, you can modify the script in step 2 to define the variable outside the parenthesis: logit="/home/ubuntu/test.log" && (echo "a") >> $logit

要更正此问题，您可以修改第 2 步中的脚本以定义括号外的变量： logit="/home/ubuntu/test.log" && (echo "a") >> $logit

回答by Anusree

if you are using a variable name in the shell command, you must concatenate it with +sign.

如果在 shell 命令中使用变量名，则必须将其与+符号连接。

for example :

例如 ：

if you have two files, and you are not going to hard code the file name, instead you want to use the variable name
"input.txt" = x
"output.txt" = y

如果您有两个文件，并且您不打算对文件名进行硬编码，而是想使用变量名
"input.txt" = x
"output.txt" = y

then ('shell command within quotes' + x > + y)

then ('引号内的 shell 命令' + x > + y)

it will work this way especially if you are using this inside a python program with os.system command probably

它会以这种方式工作，特别是如果您在带有 os.system 命令的 python 程序中使用它可能

回答by Rahul Rajput

This might be the case too.

这也可能是这种情况。

you have not specified the file in a variable and redirecting output to it, then bash will throw this error.

您没有在变量中指定文件并将输出重定向到它，那么 bash 将抛出此错误。

files=`ls`
out_file = /path/to/output_file.t
for i in `echo "$files"`;
do
    content=`cat $i` 
    echo "${content}  ${i}" >> ${out_file}
done

out_filevariable is not set up correctly so keep an eye on this too. BTW this code is printing all the content and its filename on the console.

out_file变量设置不正确，所以也要注意这一点。顺便说一句，此代码正在控制台上打印所有内容及其文件名。