1 - Frequently used cmds
stat
tree -if | grep -v node_modules | egrep '[.](j|t)sx?$' | xargs wc -l
2 - Gnu Tools
datetime
date
# 9999-99-99 99:99:99
# 00-23 00-23 00-59
# %t tab char
# %I 00-12
# %j 000-366
# %D MM/dd/yy
# %T hh:mm:ss
date "+%Y-%m-%d %H:%M:%S"
# timestamp, in sec
date +%s
cal
# print cal
cal
cal 9 1752