Bash Character Values ​​stdout

Question

How can you limit the number of standard output characters redirected to a file?

Answer 1

You can use Replace Commands to wrap the preliminary redirection of the output, and then use the Offset Parameter Extension to limit the number of characters as follows:

#!/bin/bash limit=20 out=$(echo "this line has more than twenty characters in it") echo ${out::limit} > /path/to/file 

Proof of concept

 $ limit=20 $ out=$(echo "this line has more than twenty characters in it"). $ echo ${out::limit} this line has more t 

Answer 2

Other methods (external)

 echo $out| head -c 20 echo $out | awk '{print substr($0,1,20) }' echo $out | ruby -e 'print $_[0,19]' echo $out | sed -r 's/(^.{20})(.*)/\1/' 

Answer 3

You cannot do this directly in the file, but you can pass through sed or head , etc., to transfer only part of the output. Or, as @SiegeX says, grab the output in the shell (but I would be wary of this if the output value could be large).