Placing every character on a new line

Use grep, in example:

$ grep -o . file
$ echo This is a sentence. | grep -o .

or fold:

$ fold -w1 file
$ echo This is a sentence. | fold -w1

Using sed replace every character with itself followed by a newline:

sed 's/./\0\n/g' -i filename

• sed $'s/./&\\\n/g' (with BSD sed)
  • Or sed 's/./&\n/g' with GNU sed
  • Doesn't include empty lines for linefeeds
• fold -w1
  • -w specifies width in characters
  • Doesn't include empty lines for linefeeds
• while IFS= read -r -n1 -d '' c; do printf %s\\n "$c"; done
  • Includes empty lines for linefeeds with -d ''
  • The only option for read specified by POSIX is -r
• gawk -F '' 'OFS="\n"{$1=$1}1'
  • Or awk 'BEGIN{FS="";OFS="\n"}{$1=$1}1' in nawk (BSD awk, the awk that comes with OS X); it doesn't work with multibyte characters though
  • Neither includes empty lines for linefeeds

All except the nawk command worked with non-ASCII characters in my environment when LC_CTYPE was set to a UTF-8 locale. None collapsed or stripped spaces.