问题描述
我试图在tcl文件中使用Unix"sed"命令格式，如下所示:(将多个空格更改为一个空格)
I'm trying to use the Unix "sed" command form within a tcl file, like this:(to change multiple spaces to one space)
exec /bin/sed 's/ \+/ /g' $file
我还尝试了exec /bin/sed 's/ \\+/ /g' $file(一个额外的反斜杠)
I also tried exec /bin/sed 's/ \\+/ /g' $file (an extra backslash)
没有任何版本可以正常工作，并且出现错误
none of the version work, and I get the error
/bin/sed: -e expression #1, char 1: Unknown command: `''
从Linux终端运行时，该命令运行正常
The command works fine when run from a linux terminal
我在做什么错了?
推荐答案
您做错了什么是使用'(单引号)字符.它们对Tcl 完全没有特殊意义. Tcl中的等效项是将一个单词括在{大括号}中；它完全不对里面的字符进行任何特殊处理.因此，您想要做的是:
What you're doing wrong is using ' (single quote) characters. They're not special to Tcl at all. The equivalent in Tcl is enclosing a word in {braces}; it gives no special treatment at all to the characters inside. Thus, what you seek to do would be:
exec /bin/sed {s/ +/ /g} $file
请介意，如果您要做的事情更复杂，并且Tcl限制了整个单词不被引用，那么您可以选择这样做:
Mind you, if you're doing something more complex and the restriction of Tcl to whole-words being unquoted, then you might instead go for this:
exec /bin/sh -c "sed 's/ +/ /g' $file"
或者， real 惯用的Tcl只是不将sed用于以下简单的操作:
Or, real idiomatic Tcl just doesn't use sed for something this simple:
set f [open $file]
set replacedContents [regsub -all { +} [read $f] " "]
close $f
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