One of the Linux command line learning notes

Common commands:

Pwd:print working directory, view the current working directory;

CD ~user_name: Enter the user's home directory;

[Email protected] ~]# CD ~bob[[email protected] bob]#

ln file Link: Create a hard link;

Note: Hard links cannot refer to files that are not on the same partition

Hard links cannot refer to directories

LN-S Item Link: Create a soft link;

Note: Soft links can refer to the table of contents

Type: Displays the types of a command;

Which: Displays the location of an executable command that does not work for bash built-in commands and alias;

Man: (Category of Man)

1 Users commands--General user commands
2 programming interfaces Kernel System calls--programming interface for kernel systems calls
3 programming interfaces to the C Library--c programming interface of the language library
4 special files such as device nodes and drivers--special file such as device number and driver
5 file Format formats--
6 games and amusements such as screen savers--game Entertainment
7 miscellaneous--Miscellaneous
8 System Administration commands--Administrator command related

Man 5 passwd: View the fifth part of the man document of the passwd command;

Apropos: Display the appropriate command

[Email protected] ~]# apropos FLOPPYFD (4)-Floppy disk Devicefdformat (8)-Low-level format a FL Oppy diskmbadblocks (1)-tests a floppy disk, and marks the bad blocks in the Fatmformat (1)-Add an MSDO S filesystem to a low-level formatted floppy disk

Whatis: Displays a simple description of a command

[Email protected] ~]# Whatis Lsls (1)-List directory Contentsls (1p)-List directory Conten Ts

Info about actions:

?—— Display Command Help
PgUp or Backspace--display previous page
PgDn or Space--display next page
n Next--display the Next node
P Previous--display the Previous node
U up--display The parent node of the currently displayed
node, usually a menu.
Enter--follow the hyperlink at the cursor location
Q--quit

/usr/share/doc: This directory has many programs to help the document;

Use alias to create your own commands:

[[email protected] ~]# alias foo= "cd /usr;ls -l;cd -" [[email protected ] ~]# foototal 300dr-xr-xr-x.   2 root root  81920 feb  13 08:29 bindrwxr-xr-x.   2 root root   4096 jun   9  2014 etcdrwxr-xr-x.   2 root root   4096  jun  9  2014 gamesdrwxr-xr-x. 177 root root  16384  dec 21 11:16 includedr-xr-xr-x.  49 root root   4096  feb 13 08:28 libdr-xr-xr-x. 204 root root 135168 dec 21  11:17 lib64drwxr-xr-x.  46 root root  12288 Dec 21  11:14 libexecdrwxr-xr-x.  12 root root   4096 dec 21  10:08 localdr-xr-xr-x.   2 root root  20480 feb 13 08:29 sbindrwxr-xr-x.  330 root root  12288 Dec 21 11:17 sharedrwxr-xr-x.    4 root root   4096 Dec 21 10:08 srclrwxrwxrwx.    1 root root     10 Dec 21 10:08 tmp -> &NBSP, .... /var/tmp/root[[email protected] ~]#

(Use Unalias to dismiss the command defined by alias: Unalias foo)

Type alias directly to see the system-defined alias:

[[email protected] ~]# aliasalias cp= ' cp-i ' Alias egrep= ' Egrep--color=auto ' Alias fgrep= ' Fgrep--color=auto ' Alias foo= '  CD/USR;LS-L;CD-' Alias grep= ' grep--color=auto ' Alias l.= ' ls-d. *--color=auto ' Alias ll= ' Ls-l--color=auto ' Alias ls= ' ls --color=auto ' Alias mv= ' mv-i ' Alias perlll= ' eval ' perl-mlocal::lib ' Alias rm= ' rm-i ' Alias Which= ' Alias | /usr/bin/which--tty-only--read-alias--show-dot--show-tilde '

Redirect: (0 for standard input, 1 for standard output, 2 for standard error output)

Output redirection

[[email protected] ~]# ls -l >  test.txt     #重定向 [[email protected] ~]# cat test.txttotal 64- Rwxr-xr-x. 1 root root  148 feb 27 05:00 0227_2.sh-rwxr-xr-x.  1 root root  696 feb 27 05:53 02273.sh......drwxr-xr-x. 7  root root 4096 nov 20 16:49 vmware-tools-distrib 

[Email protected] ~]# (CD/USR;LS-L;CD-) >>test.txt #追加重定向 [[email protected]tos7rzc ~]# Cat Test.txttotal 64-RW Xr-xr-x. 1 root root 148 Feb 05:00 0227_2.sh......drwxr-xr-x.   7 root root 4096 16:49 vmware-tools-distribtotal 300dr-xr-xr-x.   2 root root 81920 Feb 08:29 bindrwxr-xr-x. 2 root root 4096 June 9 etc

(connected up and down to see) ... lrwxrwxrwx. 1 root root Dec 10:08 tmp. /var/tmp/root

Error output redirection:

[Email protected] ~]# ls/noexist 2>err.txtyou have new mail in/var/spool/mail/root[[email protected] ~]# cat Err.txt Ls:cannot access/noexist:no such file or directory

REDIRECT StdOut and stderr to the same file

$ ls-l/bin/usr > Ls-output.txt 2>&1

Or

$ ls-l/bin/usr &> ls-output.txt

$ ls-l/bin/usr &>> ls-output.txt

Uniq-Outputs or filters duplicate rows;

tee– reads input from standard input, then outputs to standard output and file;

This article is from "Sunshine Kiss" blog, please make sure to keep this source http://kissofsun.blog.51cto.com/9686609/1617667

One of the Linux command line learning notes