Question

这是代码：

set source_failed = `cat mine.log`

set dest_failed = `cat their.log`

foreach t ($source_failed)
  set isdiff = 0
  set sflag = 0
  foreach t2 ($dest_failed)
    if ($t2 == $t) then
      set sflag = 1
      break
    endif
  end
  ...
end

问题是内部foreach循环在前10次迭代中运行正常。在那次迭代之后，我突然得到了

foreach: no match

此外，我正在迭代字符串数组，而不是文件。这个错误背后的原因是什么？

Answer 1

问题是（可能）mine.log和/或their.log包含特殊的通配符，例如*或?。 shell将尝试将其扩展为文件。这种偶然模式没有匹配，因此错误＆＃34;不匹配＆＃34;。

防止此行为的最简单方法是将set noglob添加到顶部。来自tcsh(1)：

    noglob  If set, Filename substitution and Directory stack  substitution
           (q.v.)  are  inhibited.   This  is most useful in shell scripts
           which do not deal with filenames, or after a list of  filenames
           has been obtained and further expansions are not desirable.

您可以使用set glob重新启用此行为。

另外，您可以使用:q。来自tcsh(1)：

Unless  enclosed in `"' or given the `:q' modifier the results of variable
substitution may eventually be command and  filename  substituted.

[..]

When the `:q' modifier is applied to a substitution the variable will expand
to multiple words with  each  word  sepa rated  by  a blank and quoted to
prevent later command or filename sub stitution.

但是在使用变量时需要非常小心引用。在下面的示例中，如果您不添加引号（echo），set noglob is much easier命令将失败：

set source_failed = `cat source`

foreach t ($source_failed:q)
    echo "$t"
end

foreach随机不匹配

1 个答案: