Unit 2: Running Command and Getting Help

commands have the following syntax: command [options][arguments]

* display all the files include hidden files
# ls --all | # ls -a

* combine -a and -l options
# ls -a -l | # ls -al

* list /tmp directory
# ls -l /tmp

* copy some files to /tmp directory
# cp *.* /tmp

* see user “root”'s password status
# passwd -S root

* add a new user user2
# useradd user2

some simple commands
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* show date
# date +%D //(mm/dd/yyyy)
# date +%T //(h:m:s)

* show 2006年6月的calendar
# cal 6 2006

* 将2006年的日历写入2006text
# cal 2006 > 2006text
# cat 2006text

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getting help：
* whatis/man/info/--help/doc
# whatis ls
# date --help
# man ls //一般使用1，5，8章节，按Q退出