linux 命令--文件操作

1. 查看 系统信息--   uname  -- http://www.cyberciti.biz/faq/command-to-show-linux-version/ 

[krystal@localhost survey]$ uname -r
3.18.3-201.fc21.x86_64
[krystal@localhost survey]$ uname -mrs
Linux 3.18.3-201.fc21.x86_64 x86_64
[krystal@localhost survey]$ uname -a
Linux localhost.localdomain 3.18.3-201.fc21.x86_64 #1 SMP Mon Jan 19 15:59:31 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

 

2. 比较文件 -- sdiff/diff  http://www.cyberciti.biz/faq/how-do-i-compare-two-files-under-linux-or-unix/

[krystal@localhost Public]$ cat file1
this is file1.
now below is the content. this line is the same.
only file1 has this line.
[krystal@localhost Public]$ cat file2
this is file2.
now below is the content. this line is the same.
[krystal@localhost Public]$ sdiff file1 file2
this is file1.                              |    this is file2.
now below is the content. this line is the same.        now below is the content. this line is the same.
only file1 has this line.                      <

3. 　获得所有的用户名 -- cut -f 1 -d ":" /etc/passed

 　　cut: -f 获得第一列， -d 定义定界符号

[krystal@localhost nginx]$ cut -f 1 -d ":"  /etc/passwd
root
bin
daemon
adm
lp
...<more>

4.  获得用户的组 -- groups 

[krystal@localhost nginx]$ groups
krystal wheel
[krystal@localhost nginx]$ groups root
root : root
[krystal@localhost nginx]$ groups krystal
krystal : krystal wheel
默认情况下，任何普通用户都可以通过su命令获得root用户的权限，对系统进行任何的操作。为了加强系统安全，Linux提供一个管理员组，只有属于这个组的用户才能使用su命令获得root权限，这个组通常为wheel.

 5. 远程传输文件 -- scp 

#从rivendell.fantasticsid.com拷贝id_rsa.pub文件到本地Downloas文件夹(需要配置远程服务器的github.)
[krystal@localhost ~]$ scp jy@rivendell.fantasticsid.com:/home/jy/.ssh/id_rsa.pub ~/Downloads/
jy@rivendell.fantasticsid.com's password: 
id_rsa.pub                                                                                                                                        100%  750     0.7KB/s   00:01  

 6. 复制文件内容到剪切板 -- xclip

#1. pipe the output into xclip to be copied into the clipboard:
$cat file | xclip

#2. To paste the text you just copied, you shall use:
$xclip -o

#3. To simplify life, you can setup an alias in your .bashrc file as I did:
alias "c=xclip"
alias "v=xclip -o"
To see how useful this is, imagine I want to open my current path in a new terminal window (there may be other ways of doing it like Ctrl+T on some systems but this is just for illustration purposes):

Terminal 1:
pwd | c
Terminal 2:
cd `v`
Notice the ` ` around v. This executes v as a command first and then substitutes it in-place for cd to use.

#4. cat file | xclip` only copies the content to the 'X' clipboard, if you want to paste somewhere else other than a 'X' application, try this one: 
cat file | xclip -selection clipboard

 7. 自定义命令别名 -- alias 

#1. show all command aliases  for user krystal
[krystal@localhost ~]$ alias
alias egrep='egrep --color=auto'
alias fgrep='fgrep --color=auto'
alias grep='grep --color=auto'
alias l.='ls -lh -d .* --color=auto'
alias ll='ls -lh --color=auto'
alias ls='ls --color=auto'
alias vi='vim'
alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

#2. edit /etc/bashrc or ~/.bashrc to add alias permanently.
#alias of commands
alias ll='ls -lh --color=auto'
alias l.='ls -lh -d .* --color=auto''