tcl help – removing non-printable characters

[Paul Bishop]

This one has me stumped.  I have a process that runs using Korn shell that executes the following command:

Code:

tr -cd ‘11121540-176’ < in_file.txt > out_file.txt

This will read in the complete file and output only the specified characters (octals 11, 12, 15, and 40 through 176 inclusive).  any ideas on how I can do this in TCL?

Thanks!

Paul Bishop
Carle Foundation Hospital
Urbana, IL

Topic

[Charlie Bursell]

It looks like you are trying to get rid of unprintable characters with the exception of the tab, line feed and carriage return.

I prefer to deal in hex but something like this should work

regsub -all — {[^trnw]} $str {} newstr

It says any thing that is not a tab. CR, LF or ASCII character, delete

[Russ Ross]

There is also a couple of TCL commands listed below

Russ Ross
RussRoss318@gmail.com

[Paul Bishop]

Thanks Charlie and Russ.  

I tried using exec with the tr command but tr uses standard input so I couldn’t get it to work.  I was able to get the regsub to work that Charlie posted with one exception – there were xFF characters scattered through the file which the regsub kept converting to xC3BF.  I got around that by string mapping xFF to null first, then doing the regsub.

Thanks!

Paul Bishop
Carle Foundation Hospital
Urbana, IL

[Charlie Bursell]

Weird!  The regexp should exclude all but was was in the list.  I know /w does not include XFF

[David Barr]

Here’s how you can call “tr” from Tcl:

Code:

set str “abcx123”
set res [exec tr -d x << $str]
puts $res

I wouldn’t recommend it in this case. I’d probably use regsub instead.

[Author]

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