touch command in Linux/Unix
touch --help
touch --version
touch abc.txt
touch 123.c def.txt 123.txt hello.html
touch file{1..5}
touch 987{a..e}
touch -a abc.txt
touch -m abc.txt
touch -t YYMMDDHHMM filename
touch -t 1905290815 abc.txt
touch -d yesterday abc.txt
touch -am abc.txt
touch -r abc.txt 123.txt