RHCE _ training content (Part 2)

------- 'Man documentation'

--- // Document category:

Man manual info node GNOME document

/Usr/share/doc: other than the above three types of documents

--- // Man Document section 8

[1.] USER command 2. Kernel System Call (from user space to kernel entry point)

3. library functions 4. Special files and devices

[5.] File Format 6. Games

7. Other pages of Standard Specifications

[8.] system management commands

9. Linux kernel API (kernel call) [new]

--- // Usage

1. man 5 passwd/man 1 passwd // view the [man manual] through man, that is, display the manual page with less

2. System-> Help-> man: passwd (5)/info: GRUB

3. man-k passwd // keyword search: db generated by makewhatis command

[Makewhatis]: Create a db for all the manual pages in the specified manpath or catpath

Makewhatis [-u] [-v] [-w] [-s sections] [-c [catpath] [manpath]



------- // CUPS: common unix printing system (print operation software on RHEL)

1. http: // localhost: 631 // access provided documents and [separate management interfaces] from TCP: 631 Port

------ // Wget command

GNU Wget is a free utility for non-interactive download of files from the Web.
It supports HTTP, HTTPS, and FTP protocols, as well as retrieval through HTTP proxies.

1. wget http: // javasuctor/pub/gls/errata. repo-O/etc/yum. repos. d/errata. repo
// Configure yum to point to the Errata library on the uctor

------ // Vimtutor ---> vim tutorial


------ // Getent

Getent database [key...]

'Description'
The getent program gathers entries from the specified administrative database using the specified search keys. Where
Database is one of aliases, ethers, group, hosts, netgroup, networks, passwd, protocols, rpc, services or shadow.

1. getent hosts RHEL

2. getent passwd Jacky // equivalent to grep Jacky/etc/passwd

------ // Traceroute:-print the route packets trace to network host

1. traceroute-Tn www.redhat.com //-T: use tcp syn for probes (use tcp syn [establish connection] to detect)
//-N: Do not map IP to hostname when displaying them


----- 'Increase the swap file size

1. dd If =/dev/Zero of = swapfile BS = 1 m COUNT = 100 // create a m empty file swapfile

2. mkswap swapfile

3. Swapon swapfile // activate

4. Swapon-S/free/top // view all swap files or partitions

5. Mount-A (write the fstab file) // the RC. sysinit initialization script is activated upon restart. The system will be automatically mounted after it is started.

------ 'Create swap partition'

1. fdisk/dev/VDA // create/dev/vda6

2. mkswap/dev/vda6

3. Mount-A // written in fstab and automatically activated after restart
UUID = a7feceb6-4203-40b7-ab16-979e5c502693 swap defaults 0 0

4. Swapon/dev/vda6 // activation; swapoff/dev/vda6 can be removed. Remember to delete the records in fstab.

5. Swapon-S/top/free // view swap increase