how to use sed from a tcl file
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
I also tried exec /bin/sed 's/ \\+/ /g' $file (an extra backslash)
none of the version work, and I get the error
/bin/sed: -e expression #1, char 1: Unknown command: `''
The command works fine when run from a linux terminal
What am I doing wrong?
Answer
What am I doing wrong?
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
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"
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