perl -petr/ -~//cd a.txt>b.txt

perl -i -petr/ -~//cd a.txt

#include<stdio.h>
k;main(){FILE*f=fopen("a.txt","rb");FILE*g=fopen("b.txt","w");while(!feof(f))(k=getc(f))>31&&k<127&&putc(k,g);}

file("b.txt","w").write(filter(lambda x:'~'>=x>' ',file("a.txt").read()))

+[[->+>+<<]>>>++++++++[->++++++++++++<<---->]>--[<<[->]>[<]>-]<+<[[-]>-<]>[[-]<<.>>]<<[-]<,]

bf strip.bf < a.txt > b.txt

+[(->+>+)3>8+(->12+<<4-)>2-[<<[->]>[<]>-]<+<([-]>-)>([-]2<.)2<[-]<,]

Set  in [c]:  '1'
Loop start   ([c]  of 1  to 999999999)
   Read from file  'a.txt' into [T] (read from [c], 1 bytes)
   Modify text  '[T]' into [R] (code in Hex)
   Set  in [N]:  '&H[R]' (calculate)
   If  True: '([N]=10)'
      Write into file  'b.txt' line '' (Append)
   End If
   If  True: '([N]>31)&([N]<127)'
      Write into file  'b.txt' line '[T]' (Append, no linefeed)
   End If
Loop end

(gc -raw a.txt) -replace"[^ -x7e]","">b.txt

(gc -raw a.txt) -replace"[^ -x7e]","">a.txt

IO.write (f="a.txt"),IO.read(f).gsub(/p{Cntrl}/,'')

[^ -~]