Comments for Frequently Asked Questions About Linux / UNIX

Comment on Clear Linux / UNIX BASH Shell Command Line Cache / History by Faisal Ali

Faisal Ali — Tue, 21 May 2013 21:09:42 +0000

hi all,
i realy very very happy of this web site
because i need some thing related linux
commands so i just type and get all details
best regards
and God Blease you

Comment on Regular Expressions In grep by answer

answer — Tue, 21 May 2013 14:33:44 +0000

Jason, you can use the “word boundary” expression, which depending on what tool you’re using can be either \b or \<
* is a quantifier, so "c*" would match "zero, one or more 'c' characters". You need exactly one c followed by anything, that would be:
\bc.*

Comment on OpenBSD: Configure Network Interface As A Bridge / Network Switch by Paul

Paul — Tue, 21 May 2013 12:27:45 +0000

Well, if you need to give bridge an address, don’t do it on physical interface. Once this particular interface goes down, you won’t be able to connect to bridge via any other interface.

Use vether* for this purpose. Give it address and add to a bridge. It is always-up and will be reachable as long as at least one physical interface of bridge is up.

Comment on HowTo: Linux / UNIX List Just Directories Or Directory Names by Nageswara Rao Orsu

Nageswara Rao Orsu — Tue, 21 May 2013 11:29:53 +0000

ls -d */ or ls -ld */ (Use these commands to display only directories in current user)
cd /etc
ls -ld */ ( Use these two commands to display only directories for all users including root)

Comment on What is The Role Of the System Administrator? by sunilkumar

sunilkumar — Tue, 21 May 2013 09:51:08 +0000

what i have to do? i want to become a sys admin in any company. i completed my diploma in computers. 10+3 (polytechnic). please help me.

Comment on Linux: Check Ram Speed and Type by Kalin Mandaliev

Kalin Mandaliev — Tue, 21 May 2013 09:07:17 +0000

root@weba:~# dmidecode -t 17
# dmidecode 2.11
SMBIOS 2.7 present.
Handle 0x002C, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x002A
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: 4096 MB
	Form Factor: DIMM
	Set: None
	Locator: P1-DIMMA1
	Bank Locator: Node0_Bank0
	Type: DDR3
	Type Detail: Registered (Buffered)
	Speed: 1333 MHz
	Manufacturer: Nanya
	Serial Number: C9542A26
	Asset Tag: Dimm0_AssetTag
	Part Number: NT4GC72B8PG0N
	Rank: 2
	Configured Clock Speed: 1333 MHz
Handle 0x002E, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x002A
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: 4096 MB
	Form Factor: DIMM
	Set: None
	Locator: P1-DIMMA2
	Bank Locator: Node0_Bank0
	Type: DDR3
	Type Detail: Registered (Buffered)
	Speed: 1333 MHz
	Manufacturer: Nanya
	Serial Number: AE5A2A29
	Asset Tag: Dimm1_AssetTag
	Part Number: NT4GC72B8PG0N
	Rank: 2
	Configured Clock Speed: 1333 MHz
Handle 0x0030, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x002A
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: P1-DIMMA3
	Bank Locator: Node0_Bank0
	Type: Unknown
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Dimm2_Manufacturer
	Serial Number: Dimm2_SerNum
	Asset Tag: Dimm2_AssetTag
	Part Number: Dimm2_PartNum
	Rank: Unknown
	Configured Clock Speed: Unknown
Handle 0x0032, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x002A
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: P1-DIMMB1
	Bank Locator: Node0_Bank0
	Type: Unknown
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Dimm3_Manufacturer
	Serial Number: Dimm3_SerNum
	Asset Tag: Dimm3_AssetTag
	Part Number: Dimm3_PartNum
	Rank: Unknown
	Configured Clock Speed: Unknown
Handle 0x0036, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x0034
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: P2-DIMME1
	Bank Locator: Node1_Bank0
	Type: Unknown
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Dimm0_Manufacturer
	Serial Number: Dimm0_SerNum
	Asset Tag: Dimm0_AssetTag
	Part Number: Dimm0_PartNum
	Rank: Unknown
	Configured Clock Speed: Unknown
Handle 0x0038, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x0034
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: P2-DIMME2
	Bank Locator: Node1_Bank0
	Type: Unknown
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Dimm1_Manufacturer
	Serial Number: Dimm1_SerNum
	Asset Tag: Dimm1_AssetTag
	Part Number: Dimm1_PartNum
	Rank: Unknown
	Configured Clock Speed: Unknown
Handle 0x003A, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x0034
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: P2-DIMME3
	Bank Locator: Node1_Bank0
	Type: Unknown
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Dimm2_Manufacturer
	Serial Number: Dimm2_SerNum
	Asset Tag: Dimm2_AssetTag
	Part Number: Dimm2_PartNum
	Rank: Unknown
	Configured Clock Speed: Unknown
Handle 0x003C, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x0034
	Error Information Handle: Not Provided
	Total Width: 72 bits
	Data Width: 64 bits
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: P2-DIMMF1
	Bank Locator: Node1_Bank0
	Type: Unknown
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Dimm3_Manufacturer
	Serial Number: Dimm3_SerNum
	Asset Tag: Dimm3_AssetTag
	Part Number: Dimm3_PartNum
	Rank: Unknown
	Configured Clock Speed: Unknown
root@weba:~#

Comment on Top 5 Linux Video Editor Software by Omar Abdallah

Omar Abdallah — Tue, 21 May 2013 01:38:07 +0000

I’ve used record my desktop, its very easy, with decent audio and video, You can adjust video and audio quality.

Comment on HowTo: grep Text Between Two Words in Unix / Linux by jwhendy

jwhendy — Mon, 20 May 2013 23:28:33 +0000

I have the same inquiry as Surya — how do you omit the start and end regexp’s?

Comment on Linux / UNIX: Generating random password with mkpasswd by Bibelo

Bibelo — Mon, 20 May 2013 22:02:02 +0000

mkpasswd on Ubuntu is as the manpage says a frontend to crypt. Means it encrypts an word given as input. If you don’t type anything it will still generate something different each time for some reason (because of a salt ?).

mkpasswd is totally different on RHEL/CentOS.

Comment on RHEL / Fedora /CentOS Linux: Set RPM Build Environment by CrayXMP

CrayXMP — Mon, 20 May 2013 21:08:01 +0000

In CentOS6/SL6, the package of scripts fedora-rpmdevtools is available as rpmdevtools.
See https://fedorahosted.org/rpmdevtools/

Comment on scp: Do not Overwrite Existing File On Linux or Unix System by jet

jet — Mon, 20 May 2013 19:45:49 +0000

mount the resource using sshfs and use regular file manager (if you do stuff manually)

Comment on Ubuntu Linux Vim Sorry, the command is not available in this version: syntax on by John Coleman

John Coleman — Mon, 20 May 2013 17:30:02 +0000

DOH! DUH! Now my highlighting works. Thanks.

Comment on Debian / Ubuntu Linux Setting a Default Gateway by Alec

Alec — Mon, 20 May 2013 15:25:33 +0000

Rajesh,

In Ubuntu, you can either add the ‘nameserver’ lines in /etc/resolv.conf like “shutty” shows, or use the recommended method in Ubuntu Precise (12.04 LTS) by adding “dns-nameservers ” and “dns-search ” in /etc/network/interfaces, like so:

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.3.1
netmask 255.255.255.0
# dns-* options are implemented by the resolvconf package, if installed

dns-nameservers 8.8.8.8
dns-search lab.internal

Comment on Linux / UNIX: Untar / Extract a .lzma Tar Ball by binu

binu — Mon, 20 May 2013 15:14:01 +0000

thanks you !

Comment on Hide the Apache Web Server Version number with ServerSignature and ServerTokens directives by roberto

roberto — Mon, 20 May 2013 09:21:40 +0000

@ Verma, this will only remove apache version name

Comment on What is The Role Of the System Administrator? by Mihir

Mihir — Mon, 20 May 2013 07:54:25 +0000

There is scope in System Administration jobs

Comment on How To Use Proxy Server To Access Internet at Shell Prompt With http_proxy Variable by nixCraft

nixCraft — Mon, 20 May 2013 06:50:29 +0000

Noop.

HTH.

Comment on Ubuntu Linux: Turn On Exec-Shield Buffer Overflow Protection by Marcello

Marcello — Mon, 20 May 2013 06:22:55 +0000

No wait, the article is the very answer to my question! Doh!

Guess that’s what you get if you post before morning coffee reaches your brain cells :-P

Comment on Ubuntu Linux: Turn On Exec-Shield Buffer Overflow Protection by Marcello

Marcello — Mon, 20 May 2013 06:20:58 +0000

Hi, thanks for the tip. I have one question, though.
On my machine dmesg says NX protection is active

me@mymachine:~$ dmesg | grep –color ‘[NX|DX]*protection’
[ 0.000000] NX (Execute Disable) protection: active

but sysctl says exec-shield is an unknown key:

sudo sysctl kernel.exec-shield
error: “kernel.exec-shield” is an unknown key

I take this as a hint that NX protection is enabled and I can’t disable it. Am I right ? Thank you.

Comment on How To Use Proxy Server To Access Internet at Shell Prompt With http_proxy Variable by Nobody!!

Nobody!! — Mon, 20 May 2013 05:32:37 +0000

I’m a Student.. I’ve Lab Exams comming up.. Programs are too Lengthy..
I’m Slow with Keyboard..

Do the above Export Command need SuperUser Privilege??