Delete empty lines using sed
You may have spaces or tabs in your "empty" line. Use POSIX classes with sed to remove all lines containing only whitespace:
sed '/^[[:space:]]*$/d'A shorter version that uses ERE, for example with gnu sed:
sed -r '/^\s*$/d'(Note that sed does NOT support PCRE.)
I am missing the awk solution:
awk 'NF' fileWhich would return:
xxxxxxyyyyyyzzzzzzHow does this work? Since NF stands for "number of fields", those lines being empty have 0 fiedls, so that awk evaluates 0 to False and no line is printed; however, if there is at least one field, the evaluation is True and makes awk perform its default action: print the current line.
sed '/^$/d' should be fine, are you expecting to modify the file in place? If so you should use the -i flag.
Maybe those lines are not empty, so if that's the case, look at this question Remove empty lines from txtfiles, remove spaces from start and end of line I believe that's what you're trying to achieve.