a "most recent" command showing file listing of mobi, pdf and epub across sub-directories sorted by time

.zshrc

# Show the most recent files of type mobi, pdf or epub, sorted with most recent at the bottom. Works on files and subdirectories of the current directory. 

# Useful references:
# find -printf is not POSIX. `-printf` becomes `-print0 | xargs -0 stat -f`
# need to convert format specifiers as well. 
# '%A@ %Ab %Ad %AY %AH:%AM || %P' shows last access time in seconds since the epoch. the month, day, year and time, a "||" separator, then filename. 
# POSIX's `find` printf arguments: https://man7.org/linux/man-pages/man1/find.1.html

# POSIX version (Linux)
alias mr="find . -type f \( -iname '*.pdf' -o -iname '*.mobi'  -o -iname '*.epub' \) -printf '%A@ %Ab %Ad %AY %AH:%AM || %P \n' | sort -n | cut -f2- -d\" \""

# Less pretty Mac OS version. 
# `mra` version uses the %a argument to the stat command, showing most recently accessed. 
# `mrm` version uses the %m argument to the stat command, showing most recently modified. 
alias mra="find . -type f \( -iname '*.pdf' -o -iname '*.mobi'  -o -iname '*.epub' \) -print0 | xargs -0 stat -f '%a %N' | sort -n"
alias mrm="find . -type f \( -iname '*.pdf' -o -iname '*.mobi'  -o -iname '*.epub' \) -print0 | xargs -0 stat -f '%m %N' | sort -n"