Hello!!
As it says in the title, I need to remove the white spacing that separate only by a white spacing to two lines, as you see in the image, the white spacing that have a green line, are the ones I need to remove, but the multiple white spacing that are with a red line, I do not want to remove them, the ones with the green line, are separated by only a white spacing, I do not know if with AWK or SED or CUT will work, the problem is that I do not know how to do it, thank you for your help.
I tried to do it with SED and with AWK as follows, but it did not produce any effect
awk -F, '{gsub("\n","",$1); print}' archivo.txt
sed 's/ //g' input.txt > no-spaces.txt
Assumptions:
If GNU sed which supports -z (slurp) option and \n notation is
available. would you please try:
sed -Ez "s/([^\n]\n)\n([^\n])/\1\2/g" input.txt > no-spaces.txt
Example of input.txt:
line1
line2 # following blank line should be removed
line3 # following blank lines should be kept
line4
Output:
line1
line2 # following blank line should be removed
line3 # following blank lines should be kept
line4
Sed normally processes the input line by line. That is why we cannot process
the input across multiple lines. The -z option changes the behavior by
setting the input line separator to the NUL character.
([^\n]\n) matches the last character of non-blank line. \1 is set as a bac
kreference.\n is the blank line in between (to be removed).([^\n]) matches the first character of the following non-blank line. \2 is
set as a backreference.Btw following will work with any POSIX-compliant sed with a help of bash:
#!/bin/bash
# define newline character for replacement
NL=$'\\\n'
sed -E '
:l
N
$!b l
# first slurp all lines in the pattern space
# and perform the replacements over the lines
s/([^'"$NL"']'"$NL"')'"$NL"'([^'"$NL"'])/\1\2/g
' input.txt > no-spaces.txt