Linux command Help

Linux command Help

2. The path to the Shell program search executable file is defined in the PATH environment variable

   [Email protected] ~]# echo $PATH
   

   /usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/java/jdk1.7.0_75/bin:/usr/local/ Zookeeper-3.4.6/bin:/usr/local/hadoop-2.6.0/bin:/root/bin

   Note: From left to right

3. See how commands are used by help command

   [[email protected] ~]# Help CD

   CD:CD [-l|-p] [dir]

   Change the shell working directory.

   Change the current directory to DIR. The default DIR is the value of the
   

   HOME Shell variable.

   The variable Cdpath defines the search path for the directory containing
   

   DIR. Alternative directory names in Cdpath is separated by a colon (:).

   A NULL directory name is the same as the current directory. If DIR begins

   With a slash (/) and then Cdpath are not used.

   If The directory is not a found, and the shell option ' cdable_vars ' is set,
   

   The word is assumed to be a variable name. If the variable has a value,

   Its value is used for DIR.

   Options:
   

   -L Force Symbolic links to be followed

   -p Use the physical directory structure without following symbolic

   Links

   The default is to follow symbolic links, as if '-l ' were specified.
   

   Exit Status:
   

   Returns 0 If the directory is changed; Non-zero otherwise.

4. User manual (Manual) Man COMMAND

   Mans LS

   LS (1) User Commands ls (1)

   NAME
   

   Ls-list Directory Contents

   Synopsis
   

   ls [OPTION] ... [FILE] ...

   DESCRIPTION
   

   List information about the FILEs (the current directory by default). Sort entries

   Alphabetically if none Of-cftuvsux nor--sort.

   Mandatory arguments to long options is Mandatory for short options too.

   -A,--all
   

   Do not ignore entries starting with.

   -A,--almost-all
   

   Do not list implied. and..

   --author
   

   With-l, print the author of each file

   -B,--escape
   

   Print octal escapes for nongraphic characters

   --block-size=size
   

   Use Size-byte blocks. See SIZE format below

6. Info Page # Info COMMAND

8. Help documentation for the program itself

   Readme

   INSTALL

   ChangeLog

10. Internal command assistance: # Help command

    Hash command: The path result of the external command that the shell has searched for is cached into the KV (key-value) store;

    [[email protected] ~]# hash

    Hitscommand

    1/bin/grep

    3/bin/cat

    1/bin/ls

12. History command

14. Manage command history, when you log in to the shell, the commands that are recorded in the command history file are read: ~/.bash_history

    History
    

    -A: Append the newly executed command history list to the history file in this session

    -D: Delete the command specified in history

    -C: Empty command history

    
    

    [email protected] ~]# cat. bash_history

    chmod u-w/etc/sudoers

    sudo ifconfig

    Shutdown-h now

    Ifconfig

    Ping www.baidu.com

    Shutdown-h now

    Ifconfig

    Service Network restart

    Ping www.baidu.com

    Shutdown-h now

16. Linux Quick Action

    
    

18. !#: Call history in the # command

    For example, through the history view is as follows:

    1022 pwd

    1023 Cat. Bash_history

    1024x768 Clear

    1025 History

    
    

    [Email protected] ~]#!1022

    Pwd

    /root

    
    

    
    

    !string: Call the last command in history that starts with a string (and then complements it)

    !: Previous command (back up)

    
    

19. External commands help get

    Mans COMMAND

    Manual page:/usr/share/man

    
    

    [Email protected] ~]# ls/usr/share/man/

    BG de es hr it man0p man1x man3 man4 man5x man7 man8x Mann PL RO SL ZH_CN cs el fi hu ja Man1 man2 man3p man4x man6 man7x man9 nl pt RU SV ZH_TW

    Da en fr id ko man1p man2x man3x man5 man6x man8 Man9x overrides Pt_br SK TR

    
    

    Note: Man1. MAN8 main functions are as follows:

    Man1: User Commands

    Man2: System call

    MAN3:C Library Call

    MAN4: Equipment files and special files

    MAN5: Configuration file format

    Man6: Games

    MAN7: Miscellaneous

    MAN8: Commands for managing classes

    
    

    [Email protected] ~]# LS/USR/SHARE/MAN/MAN8

    abrtd.8.gz iptunnel.8.gz qmqpd.8.gz

    abrt-dbus.8.gz isosize.8.gz quotacheck.8.gz

    accept.8.gz iw.8.gz quota_nld.8.gz

    accton.8.gz iwconfig.8.gz quotaoff.8.gz

    acpid.8.gz iwevent.8.gz quotaon.8.gz

    acpi_listen.8.gz iwgetid.8.gz quotastats.8.gz

    addgnupghome.8.gz iwlist.8.gz raw.8.gz

    addpart.8.gz iwpriv.8.gz rawdevices.8.gz

    adduser.8.gz iwspy.8.gz rdisc.8.gz

    agetty.8.gz kbdrate.8.gz reboot.8.gz

    alternatives.8.gz kexec.8.gz regdbdump.8.gz

    anacron.8.gz killall5.8.gz reject.8.gz

    anvil.8.gz killpgrp.8.gz reload.8.gz

21. View the LS command in which document (compressed package) LS command in man1 this path

    [Email protected] ~]# Ls/usr/share/man/man1 | grep ls.*
    

    Alsactl.1.gz

    Alsaloop.1.gz

    Alsamixer.1.gz

    False.1.gz

    Ls.1.gz

    Lsattr.1.gz

    Lscpu.1.gz

    Lshal.1.gz

    Lsinitrd.1.gz

    Lslogins.1.gz

    Mtools.1.gz

    Mtoolstest.1.gz

    Perlsec.1.gz

    Perlsolaris.1.gz

    Perlstyle.1.gz

    Perlsub.1.gz

    Perlsymbian.1.gz

    Perlsyn.1.gz

    Pulseaudio.1.gz

    Xlsatoms.1.gz

    Xlsclients.1.gz

    Xlsfonts.1.gz

    Yum-utils.1.gz

22. Text Search

    /keyword:

    Searches the end of the file from the current position with the string specified by keyword as the keyword;

    Search slave keywords

    [Email protected] ~]# vim/etc/hosts

    127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

    :: 1 localhost localhost.localdomain localhost6 localhost6.localdomain6

    192.168.1.107 Master

    192.168.1.108 Slave

    ~

    ~

    ~

    ~

    :/slave

    
    

    N: Next

    N: Previous

    ? KEYWORD:

    The string specified by keyword is the keyword, and the file header is searched from the current position;

    N: Same direction as search command, next

    N: Follow the search command in the opposite direction, previous

    
    

23. The configuration file path for the man command/etc/man.config

    [Email protected] ~]# More/etc/man.config

    # Manbin/usr/local/bin/man

    #

    # Every automatically generated MANPATH includes these fields

    #

    MANPATH/usr/man

    MANPATH/usr/share/man

    MANPATH/usr/local/man

    MANPATH/usr/local/share/man

    MANPATH/usr/x11r6/man

    #

    # Uncomment if want to include one of the These by default

    #

    # MANPATH/opt/*/man

    # MANPATH/usr/lib/*/man

    # MANPATH/usr/share/*/man

    # MANPATH/usr/kerberos/man

    #

    # Set up PATH to MANPATH mapping

    
    

    
    

    Manpath/path/to/somewhere: Indicates the new manual file search location

    
    

    # man-m/path/to/somewhere Command: Searches the command command's hand album to the specified location and displays it;

    
    

    The paragraph description in the Help manual:

    NAME

    Synopsis

    DESCRIPTION

    OPTIONS

    EXAMPLES

    AUTHOR

    REPORTING BUGS

    See ALSO

    Synopsis:
    

[]: Optional content

<>: Required Content

A|b: Two Choose one

...: The same content can appear multiple times

How to operate the man command:

Space, ^v, ^f, ^f: Flip the screen to the end of the file;

B, ^b: Flip the screen to the file header;

D, ^d: half-screen to the tail of the file;

U, ^u: Turn half screen to file header;

RETURN, ^n, E, ^e or J or ^j: Flip a line to the end of the file;

Y or ^y or ^p or K or ^k: turns a line into the file header;

Q: Exit;

#: Jump To Line #;

1 g: Back to File header

G: Turn to the tail of the file

This chapter is very useful! Must have a deep understanding Oh!!!

This article is from the "Liang blog" blog, make sure to keep this source http://7038006.blog.51cto.com/7028006/1793777

Linux command Help