Control character in a file

cursive · #1 (**permalink**) 04-25-2007

Hi All,

I am looking for a solution to capture any ASCII control character in a file
( where the ASCII control character is in decimal value from 0 to 31 and 127
( Hex value from 00 to 1F and 7F ) ) by returning any affected lines.

The intended good file should contain "ASCII printable character" where ASCII
printable character is in decimal value from 32 to 126 ( Hex value from 20 to
7E ).

Thanks in advance.

Best regards,
cursive

anbu23 · #2 (**permalink**) 04-25-2007

Removes ASCII control characters from 0 to 31 and 127

Code:

tr -d "\000-\037\177" < file

Code:

while read line 
do
       [[ -n "$( echo $line | tr -d "\000-\037\177" )" ]] && echo "$line"
done < file

ghostdog74 · #3 (**permalink**) 04-25-2007

you may also want to try awk's POSIX character classes like [:print:],[:graph:] etc...

cursive · #4 (**permalink**) 04-25-2007

Hi Anbu23,

I am not sure if I missing something here by using the given solution :
tr -d "\000-\037\177" < file because the output is still contained the control
character.

Provided a sample of the input file :
-------------------------------------------------
Monday Tuesday Wednesday
Thursday Friday
Saturday
Sunday
Number = 0.36")· )

Apple orange
Pinapple

Output file ( display lines with control character ):
---------------
>Monday Tuesday Wednesday
>Saturday
>Number = 0.36")· )
>Apple orange
>

Thanks in advance,
cursive

anbu23 · #5 (**permalink**) 04-25-2007

Code:

/db2home/training$ cat -e f
Monday Tuesday Wednesday$
Thursday Friday$
Saturday ^F$
Sunday$
Number = 0.36")· )$
$
Apple orange $
Pinapple$
^G$
/db2home/training$ tr -d "\000-\011\013-\037\177-\377" < f | cat -e
Monday Tuesday Wednesday$
Thursday Friday$
Saturday $
Sunday$
Number = 0.36") )$
$
Apple orange $
Pinapple$
$

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