The transcription of D is wrong. It should be:
sed 's/\([a-zA-Z]\+\)/\n&\n/g; s/\n\(.\)\(.*\)\(.\)\n/\3\2\1/g; s/\n//g' file.txt
also D is correct, assuming file.txt contains a list of words one per line
The transcription of D is wrong. It should be:
sed 's/\([a-zA-Z]\+\)/\n&\n/g; s/\n\(.\)\(.*\)\(.\)\n/\3\2\1/g; s/\n//g' file.txt
also D is correct, assuming file.txt contains a list of words one per line
try “flatpak remove --unused”