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How do I remove control characters?

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Contributed by Grunk on May 07, 2002 at 21:30 UTC
Q&A  > regular expressions


Description:

I have a korn shell at work that strips all the control characters (octal 041-176). I'm trying to write a job in perl to do the same to do some speed comparisons.

My question is, how do I specify to sub a range of octal values to a space (default)?
something like
s/!(octal value 041-176)/ /g

Answer: How do I remove control characters?
contributed by jsprat

Try perldoc perlop and look for the transliteration operator.

tr/\040-\176/ /c;
The 'c' option means complement the range.
Note: you may have to binmode the filehandle, depending on your OS.
Answer: How do I remove control characters?
contributed by tachyon

tr/// is better but all you needed to make your pseudocode real perl code was:

s/[^\040-\176]/ /g

Note that the control chars are \000 - \037 so these are perhaps more direct:

tr/\000-\037/ /; # best option for speed s/[\000-\037]/ /g # but this still works

Note chr 32 dec 040 octal is the space so you were double spacing your spaces by starting at \041

Answer: How do I remove control characters?
contributed by kgsz

For similiar problem (removing colors):

For shell:

cat something | perl -le 'while (<>) {chomp; s/[\000-\037]\[(\d|;)+m// +g; print ($_) };'

In generic:
# sth; sth; { s/[\000-\037]\[(\d|;)+m//g; } # sth else;
ANSI colors looks like :) ^[[number[;number]m - reset: ^[[m

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