Convert m4b to mp3 on Centos/Fedora using ffmpeg
karlofor m4b in *.m4b; do ffmpeg -i $m4b -acodec libmp3lame -ar 22050 ${m4b}.mp3; done
Bash remove spaces from file names
find . -depth -name '* *' \ | while IFS= read -r f ; do mv -i "$f" "$(dirname "$f")/$(basename "$f"|tr ' ' _)" ; done
AWK print longest line in file
awk '{ if (length($0) > max) {max = length($0); maxline = $0} } END { print maxline }' YOURFILE