The unit separator ASCII character (ASCII 31, octal 37), is visible in Vim as a `^_`. But if I print the same file to the terminal, the character is invisible. This causes the fields on a line to get stuck together: 

 # In Vim and less:
 
 first field^_second field^_last field
 
 # cat the same file to terminal:
 cat delim.txt
 first fieldsecond fieldlast field
 
 # print 2nd field with awk 
 cat delim.txt | awk 'BEGIN {FS = "\037"} {print $2}'
 second field

I suppose I can make the unit separator visible with this tr command:

 cat delim.txt | tr '\037' ':'
 first field:second field:last field

But this is rather cumbersome. Why doesn't the unit separator have a visible representation when printed to stdout in the Bash shell?