Replace multiple spaces (characters) using sed

sed_replace_multiple.sh

#!/bin/bash
#
# Replace one or more spaces (characters) with sed
# Important: there are two spaces before the * character
# Note: If you don't quote $text, echo will strip multiple spaces to just one
#

text="hello     world"
echo "$text" | sed 's/  */X/g'
#helloXworld

text="hello world"
echo "$text" | sed 's/  */X/g'
#helloXworld

# I often use it with uniq -c which would create a similar output
text=" 2   a\n1  c\n3 b"
echo -e "$text" | sed 's/  */\t/g' | sed 's/^\t//g' | sort -k1n
#1       c
#2       a
#3       b

# Alternative is to use (Note: only one space here) 
sed 's/ +//g'