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[one-liner]: Analyzing a System's BIOS from the Commandline under Fedora 10

Background

A system’s BIOS is a treasure trove of a lot of useful info about the capabilities of a computer. BIOS, which stands for Basic Input/Output System, contains information such as:

* motherboard manufacturer
* system’s serial number
* amount of RAM installed
* the CPUs speed & signature

Normally the BIOS is accessible by pressing the delete key or the F1 key.

Problem

Occasionally I’ve wanted to check out the BIOS settings of a system without having to go through the hassle of rebooting. With the help of this nifty command line tool, dmidecode, BIOS info can be had, without having to reboot.

Solution

dmidecode is a tool for dumping a computer’s DMI (some say SMBIOS) table contents in a human-readable format. This table contains a description of the system’s hardware components, as well as other useful pieces of information such as serial numbers and BIOS revision. Thanks to this table, you can retrieve this information without having to probe for the actual hardware. While this is a good point in terms of report speed and safeness, this also makes the presented information possibly unreliable.

The DMI table doesn’t only describe what the system is currently made of, it also can report the possible evolutions (such as the fastest supported CPU or the maximal amount of memory supported).

SMBIOS stands for System Management BIOS, while DMI stands for Desktop Management Interface. Both standards are tightly related and developed by the DMTF (Desktop Manage- ment Task Force).

Example output from a Thinkpad T42 laptop

When you first run the dmidecode command it tells you a summary of how many structures are present within your system’s BIOS.

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% dmidecode 
# dmidecode 2.9
SMBIOS 2.33 present.
61 structures occupying 2126 bytes.
Table at 0x000E0010.

Each structure is represented by a handle ID which is a hex value of the form 0×001F, followed by it’s type and it’s size.

System Info
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Handle 0x0000, DMI type 0, 20 bytes
BIOS Information
	Vendor: IBM
	Version: 1RETDPWW (3.21 )
	Release Date: 06/02/2006
	Address: 0xDC000
	Runtime Size: 144 kB
	ROM Size: 1024 kB
	Characteristics:
		PCI is supported
		PC Card (PCMCIA) is supported
		PNP is supported
		APM is supported
		BIOS is upgradeable
		BIOS shadowing is allowed
		ESCD support is available
		Boot from CD is supported
		Selectable boot is supported
		EDD is supported
		3.5"/720 KB floppy services are supported (int 13h)
		Print screen service is supported (int 5h)
		8042 keyboard services are supported (int 9h)
		Serial services are supported (int 14h)
		Printer services are supported (int 17h)
		CGA/mono video services are supported (int 10h)
		ACPI is supported
		USB legacy is supported
		AGP is supported
		BIOS boot specification is supported
 
Handle 0x0001, DMI type 1, 25 bytes
System Information
	Manufacturer: IBM
	Product Name: 2373B09
	Version: ThinkPad T42
	Serial Number: 99N4BVC
	UUID: 205A7001-46D4-22CB-B51D-FDE5F7FCD3CD
	Wake-up Type: Power Switch
 
Handle 0x0002, DMI type 2, 8 bytes
Base Board Information
	Manufacturer: IBM
	Product Name: 2373B09
	Version: Not Available
	Serial Number: J1ZTY5031AP
 
Handle 0x0003, DMI type 3, 17 bytes
Chassis Information
	Manufacturer: IBM
	Type: Notebook
	Lock: Not Present
	Version: Not Available
	Serial Number: Not Available
	Asset Tag: No Asset Information
	Boot-up State: Unknown
	Power Supply State: Unknown
	Thermal State: Unknown
	Security Status: Unknown
	OEM Information: 0x00000000
CPU Info
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Handle 0x0006, DMI type 4, 35 bytes
Processor Information
	Socket Designation: None
	Type: Central Processor
	Family: Pentium M
	Manufacturer: GenuineIntel
	ID: D6 06 00 00 BF B3 A3 AF
	Signature: Type 0, Family 6, Model 13, Stepping 6
	Flags:
		FPU (Floating-point unit on-chip)
		VME (Virtual mode extension)
		DE (Debugging extension)
		PSE (Page size extension)
		TSC (Time stamp counter)
		MSR (Model specific registers)
		MCE (Machine check exception)
		CX8 (CMPXCHG8 instruction supported)
		SEP (Fast system call)
		MTRR (Memory type range registers)
		PGE (Page global enable)
		MCA (Machine check architecture)
		CMOV (Conditional move instruction supported)
		PAT (Page attribute table)
		CLFSH (CLFLUSH instruction supported)
		DS (Debug store)
		ACPI (ACPI supported)
		MMX (MMX technology supported)
		FXSR (Fast floating-point save and restore)
		SSE (Streaming SIMD extensions)
		SSE2 (Streaming SIMD extensions 2)
		SS (Self-snoop)
		TM (Thermal monitor supported)
		PBE (Pending break enabled)
	Version: Intel(R) Pentium(R) M processor
	Voltage: 1.3 V
	External Clock: 400 MHz
	Max Speed: 1600 MHz
	Current Speed: 1600 MHz
	Status: Populated, Enabled
	Upgrade: None
	L1 Cache Handle: 0x000A
	L2 Cache Handle: 0x000B
	L3 Cache Handle: Not Provided
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified
...
RAM Info
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Handle 0x0007, DMI type 5, 20 bytes
Memory Controller Information
	Error Detecting Method: None
	Error Correcting Capabilities:
		None
	Supported Interleave: One-way Interleave
	Current Interleave: One-way Interleave
	Maximum Memory Module Size: 1024 MB
	Maximum Total Memory Size: 2048 MB
	Supported Speeds:
		Other
	Supported Memory Types:
		DIMM
		SDRAM
	Memory Module Voltage: 2.9 V
	Associated Memory Slots: 2
		0x0008
		0x0009
	Enabled Error Correcting Capabilities:
		None
 
Handle 0x0008, DMI type 6, 12 bytes
Memory Module Information
	Socket Designation: DIMM Slot 1
	Bank Connections: 0 1
	Current Speed: Unknown
	Type: DIMM SDRAM
	Installed Size: 1024 MB (Double-bank Connection)
	Enabled Size: 1024 MB (Double-bank Connection)
	Error Status: OK
 
Handle 0x0009, DMI type 6, 12 bytes
Memory Module Information
	Socket Designation: DIMM Slot 2
	Bank Connections: 2 3
	Current Speed: Unknown
	Type: DIMM SDRAM
	Installed Size: 1024 MB (Double-bank Connection)
	Enabled Size: 1024 MB (Double-bank Connection)
	Error Status: OK
...
Cache Info
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Handle 0x000A, DMI type 7, 19 bytes
Cache Information
	Socket Designation: Internal L1 Cache
	Configuration: Enabled, Socketed, Level 1
	Operational Mode: Write Back
	Location: Internal
	Installed Size: 32 KB
	Maximum Size: 32 KB
	Supported SRAM Types:
		Synchronous
	Installed SRAM Type: Synchronous
	Speed: Unknown
	Error Correction Type: Unknown
	System Type: Other
	Associativity: 8-way Set-associative
 
Handle 0x000B, DMI type 7, 19 bytes
Cache Information
	Socket Designation: Internal L2 Cache
	Configuration: Enabled, Socketed, Level 2
	Operational Mode: Write Back
	Location: Internal
	Installed Size: 2048 KB
	Maximum Size: 2048 KB
	Supported SRAM Types:
		Burst
	Installed SRAM Type: Burst
	Speed: Unknown
	Error Correction Type: Multi-bit ECC
	System Type: Unified
	Associativity: 8-way Set-associative
...
Port Info (USB, Infrared, Parallel, etc.)
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Handle 0x000D, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: Infrared
	External Connector Type: Infrared
	Port Type: Other
 
Handle 0x000E, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: Parallel
	External Connector Type: DB-25 female
	Port Type: Parallel Port ECP/EPP
 
Handle 0x000F, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: External Monitor
	External Connector Type: DB-15 female
	Port Type: Video Port
 
Handle 0x0015, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: Microphone Jack
	External Connector Type: Mini Jack (headphones)
	Port Type: Audio Port
 
Handle 0x0016, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: Headphone Jack
	External Connector Type: Mini Jack (headphones)
	Port Type: Audio Port
 
Handle 0x0017, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: S-Video-Out
	External Connector Type: Other
	Port Type: Video Port
 
Handle 0x0019, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: Modem
	External Connector Type: RJ-11
	Port Type: Modem Port
 
Handle 0x001A, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: Ethernet
	External Connector Type: RJ-45
	Port Type: Network Port
 
Handle 0x001B, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: USB 1
	External Connector Type: Access Bus (USB)
	Port Type: USB
 
Handle 0x001C, DMI type 8, 9 bytes
Port Connector Information
	Internal Reference Designator: Not Available
	Internal Connector Type: None
	External Reference Designator: USB 2
	External Connector Type: Access Bus (USB)
	Port Type: USB
...
CardBus Slot Info
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Handle 0x0022, DMI type 9, 13 bytes
System Slot Information
	Designation: CardBus Slot 1
	Type: 32-bit PC Card (PCMCIA)
	Current Usage: Available
	Length: Other
	ID: Adapter 0, Socket 0
	Characteristics:
		5.0 V is provided
		3.3 V is provided
		PC Card-16 is supported
		Cardbus is supported
		Zoom Video is supported
		Modem ring resume is supported
		PME signal is supported
		Hot-plug devices are supported
 
Handle 0x0023, DMI type 9, 13 bytes
System Slot Information
	Designation: CardBus Slot 2
	Type: 32-bit PC Card (PCMCIA)
	Current Usage: Available
	Length: Other
	ID: Adapter 1, Socket 0
	Characteristics:
		5.0 V is provided
		3.3 V is provided
		PC Card-16 is supported
		Cardbus is supported
		Zoom Video is supported
		Modem ring resume is supported
		PME signal is supported
		Hot-plug devices are supported
...
RAM Modules Info
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Handle 0x002C, DMI type 16, 15 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 1 GB
	Error Information Handle: Not Provided
	Number Of Devices: 2
 
Handle 0x002D, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x002C
	Error Information Handle: No Error
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 1024 MB
	Form Factor: SODIMM
	Set: None
	Locator: DIMM 1
	Bank Locator: Bank 0/1
	Type: DDR
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Not Specified
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified
 
Handle 0x002E, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x002C
	Error Information Handle: No Error
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 1024 MB
	Form Factor: SODIMM
	Set: None
	Locator: DIMM 2
	Bank Locator: Bank 2/3
	Type: DDR
	Type Detail: Synchronous
	Speed: Unknown
	Manufacturer: Not Specified
	Serial Number: Not Specified
	Asset Tag: Not Specified
	Part Number: Not Specified
 
Handle 0x002F, DMI type 18, 23 bytes
32-bit Memory Error Information
	Type: OK
	Granularity: Unknown
	Operation: Unknown
	Vendor Syndrome: Unknown
	Memory Array Address: Unknown
	Device Address: Unknown
	Resolution: Unknown
 
Handle 0x0030, DMI type 19, 15 bytes
Memory Array Mapped Address
	Starting Address: 0x00000000000
	Ending Address: 0x0007FFFFFFF
	Range Size: 2 GB
	Physical Array Handle: 0x002C
	Partition Width: 0
 
Handle 0x0031, DMI type 20, 19 bytes
Memory Device Mapped Address
	Starting Address: 0x00000000000
	Ending Address: 0x0003FFFFFFF
	Range Size: 1 GB
	Physical Device Handle: 0x002D
	Memory Array Mapped Address Handle: 0x0030
	Partition Row Position: 1
 
Handle 0x0032, DMI type 20, 19 bytes
Memory Device Mapped Address
	Starting Address: 0x00040000000
	Ending Address: 0x0007FFFFFFF
	Range Size: 1 GB
	Physical Device Handle: 0x002E
	Memory Array Mapped Address Handle: 0x0030
	Partition Row Position: 1
...
Pointing Device Info
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Handle 0x0033, DMI type 21, 7 bytes
Built-in Pointing Device
	Type: Track Point
	Interface: PS/2
	Buttons: 3
 
Handle 0x0034, DMI type 21, 7 bytes
Built-in Pointing Device
	Type: Touch Pad
	Interface: PS/2
	Buttons: 0
...
The End
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End Of Table

There are some additional handles related to system logging, hardware security, and OEM information that I ommited to keep this post from just becoming a complete dump of the output but needless to say dmidecode is a pretty exhaustive and sweet command.

Check out the dmidecode website or the man page for more information.

Keeping CentOS 5 OpenVZ images up to Date with Yum

Now that I’ve been using OpenVZ for several months I’d gotten to the point where I wanted/needed to “yum update” all my VEs. I currently have 11 images running on my OpenVZ Server. I thought I could just vzctl exec … yum -y update all the VEs, but quickly ran into some issues with this brute force approach. Doing the yum -y update broke several of my VEs so I opted to restore the unrecoverable ones from backups.

For my second attempt, I opted to do each VE independently, to get a better understanding of what the best approach would be for doing mass upgrades like this now, and in the future. The first hurdle to overcome had to do with some of the VEs running out of memory (RAM) during the upgrade process.

NOTE: A VE = Virtual Environment (aka. a virtual host), while HN = Host Node

Issue #1, not enough RAM for yum to run

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# RAM budgets for VEs
 
# NOTE: values are in # of pages (1 pg. = 4K)
 
% (printf "vm feature held maxheld barrier limit failcnt\n"; grep privvm /proc/bc/1*/resources)|column -t
vm                       feature      held    maxheld  barrier  limit   failcnt
/proc/bc/101/resources:  privvmpages  31904   82215    65536    69632   2
/proc/bc/102/resources:  privvmpages  119803  196620   166400   179200  9517
/proc/bc/103/resources:  privvmpages  27125   35974    65536    69632   0
/proc/bc/104/resources:  privvmpages  56251   107250   104960   115200  0
/proc/bc/105/resources:  privvmpages  73559   82926    98304    103304  0
/proc/bc/106/resources:  privvmpages  30219   68097    65536    69632   0
/proc/bc/108/resources:  privvmpages  30081   84291    65536    69632   1
/proc/bc/109/resources:  privvmpages  32790   74199    98304    103304  0
/proc/bc/110/resources:  privvmpages  40497   69408    65536    69632   1
/proc/bc/111/resources:  privvmpages  26990   35371    65536    67840   0
 
# NOTE: converted the columns to megabytes (MB), it's just easier to read
 
(printf "vm feature held maxheld barrier limit failcnt\n"; grep privvm /proc/bc/1*/resources|awk '{sub($3,$3*4096/2^20) sub($4,$4*4096/2^20) sub($5,$5*4096/2^20) sub($6,$6*4096/2^20)}1')|column -t
vm                       feature      held     maxheld  barrier  limit    failcnt
/proc/bc/101/resources:  privvmpages  124.625  321.152  256      272      2
/proc/bc/102/resources:  privvmpages  467.98   768.047  650      700      9517
/proc/bc/103/resources:  privvmpages  105.957  140.523  256      272      0
/proc/bc/104/resources:  privvmpages  219.73   418.945  410      450      0
/proc/bc/105/resources:  privvmpages  287.34   323.93   384      403.531  0
/proc/bc/106/resources:  privvmpages  118.043  266.004  256      272      0
/proc/bc/108/resources:  privvmpages  117.504  329.262  256      272      1
/proc/bc/109/resources:  privvmpages  128.086  289.84   384      403.531  0
/proc/bc/110/resources:  privvmpages  158.191  271.125  256      272      1
/proc/bc/111/resources:  privvmpages  105.43   138.168  256      265      0

According to this data 4 of the 11 images had gone over their allocation of RAM. So I tried restarting these and re-running yum update within the problem VEs. Again the update failed and so I needed to increase their allocation of memory. I didn’t want to devote more memory permanently, just a enough temporarily to do the upgrade. So I used this trick to temporarily bump up a VEs allocated memory.

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# increase the RAM by 100MB
vzctl set 101 --privvmpages $((256+100))m:$((272+100))m --save
 
# ...
# do the upgrade (yum update)
# ...
 
# decrease the RAM back to the original value
vzctl set 101 --privvmpages 256m:272m --save

For the remaining 3 VEs that needed additional memory I used these commands to increase their allocations of RAM

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# cmds. to increase RAM by 100MB
vzctl set 102 --privvmpages $((650+100))m:$((700+100))m --save
vzctl set 108 --privvmpages $((256+100))m:$((272+100))m --save
vzctl set 110 --privvmpages $((256+100))m:$((272+100))m --save
 
# cmds. to decrease
vzctl set 102 --privvmpages 650m:700m --save
vzctl set 108 --privvmpages 256m:272m --save
vzctl set 110 --privvmpages 256m:272m --save

Issue #2, not enough diskspace for yum to run

The next snag I ran into had to do with a couple of the VEs running out of diskspace. And here’s the commands I used to reconfigure more diskspace.


…. Continue reading → Keeping CentOS 5 OpenVZ images up to Date with Yum »»

[one-liner]: Filtering ps from ps (redux)

As it is with UNIX & Linux there is always another way. In my previous article [one-liner]: Filtering ps from ps, one reader, Christoph, mentioned an alternative method to the one I outlined. In this case, I would consider his to be a better way, so I thought I would take a second to demonstrate this alternative method. The alternative? Use the command pgrep.

The Original Approach

My original post offered the following one-liner:

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% ps -eaf | grep "[h]ttpd"
root      2683     1  0  2008 ?        00:20:31 /usr/sbin/httpd
apache   17146  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17147  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17149  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17150  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17151  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17152  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17153  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17154  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd

This one-liner provided a list of all the httpd processes running, while filtering out the actual string from the grep httpd command.

The Alternative Approach

By using the command pgrep, the same effect can be achieved and a lot more. For starters, you can get a list of all the httpd PIDs:

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# list of httpd PIDs
 
% pgrep httpd
1608
7645
9739
10051
27712
27859

This could be useful in a shell script, if needed, to check for any running httpd processes. For example:

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# test for httpd processes
 
% [ -z "`pgrep httpd`" ] || echo "running"
running

Here are some other examples:

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# list of PIDs with corresponding command name
 
% pgrep -l httpd
1608 httpd
7645 httpd
9739 httpd
10051 httpd
27712 httpd
27859 httpd
 
# list of PIDs with corresponding command name owned by user root
 
% pgrep -l -u root httpd
1608 httpd
 
# list of PIDs, separated with a comma delimiter
 
% pgrep -d, httpd
1608,7645,9739,14119,14162,27859
 
# detailed list of httpd PIDs via ps
# NOTE: $(...) runs the command above, returning the list of PIDs to ps
 
% ps -fp $(pgrep -d, httpd)
UID        PID  PPID  C STIME TTY          TIME CMD
root      1608     1  0 Aug03 ?        00:00:05 /usr/sbin/httpd
apache    7645  1608  0 Sep04 ?        00:00:47 /usr/sbin/httpd
apache    9739  1608  0 Sep04 ?        00:01:50 /usr/sbin/httpd
apache   14119  1608  0 Sep04 ?        00:00:13 /usr/sbin/httpd
apache   14162  1608  0 Sep04 ?        00:00:13 /usr/sbin/httpd
apache   27859  1608  0 Sep04 ?        00:07:19 /usr/sbin/httpd

Thanks again to Christoph for pointing out this alternative.

NOTE: For further details regarding my one-liner blog posts, check out my one-liner style guide primer.

[one-liner]: Filtering ps from ps

Background

This is a pretty handy trick to know when you want to filter out the command you’re running, so that it’s not included in ps output. This proves handy when writing a shell script that needs to parse output from ps.

NOTE: The command ps, allows you to see all the processes being run on a UNIX/Linux system. You typically use it with the switches “-eaf” or “-ef”.

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# columns description:
# UID   = user who owns the process
# PID   = process #
# PPID  = parents' process #
# C     = 
# STIME = start time
# TTY   = terminal type (has to do with which shell command ran from)
# TIME  = system time its run
# CMD   = command (aka. program name)
 
% ps -eaf
UID        PID  PPID  C STIME TTY          TIME CMD
root         1     0  0  2008 ?        00:24:46 init [5]
root         2     0  0  2008 ?        00:00:00 [kthreadd]
root         3     2  0  2008 ?        00:01:58 [migration/0]
root         4     2  0  2008 ?        00:23:13 [ksoftirqd/0]
root         5     2  0  2008 ?        00:00:00 [watchdog/0]
root         6     2  0  2008 ?        00:02:35 [migration/1]
root         7     2  0  2008 ?        00:09:55 [ksoftirqd/1]
root         8     2  0  2008 ?        00:00:00 [watchdog/1]
root         9     2  0  2008 ?        00:06:36 [events/0]
root        10     2  0  2008 ?        00:06:16 [events/1]
root        11     2  0  2008 ?        00:00:10 [khelper]
root        54     2  0  2008 ?        00:19:26 [kblockd/0]

Problem

Here’s an example where we want to see if a program is running, so we grep the output of ps like so:

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% ps -eaf | grep httpd
root      2683     1  0  2008 ?        00:20:31 /usr/sbin/httpd
user1    13188  3984  0 12:45 pts/1    00:00:00 grep httpd
apache   17146  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17147  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17149  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17150  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17151  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17152  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17153  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17154  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd

The problem? Notice that a portion of our command, “grep httpd” is polluting our ps output. How can we get rid of it?

The Trick

You can alter what you are grepping for, without actually altering the results, by using a benign regular expression.

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% ps -eaf | grep "[h]ttpd"
root      2683     1  0  2008 ?        00:20:31 /usr/sbin/httpd
apache   17146  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17147  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17149  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17150  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17151  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17152  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17153  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd
apache   17154  2683  0 Aug30 ?        00:00:02 /usr/sbin/httpd

Explanation


…. Continue reading → [one-liner]: Filtering ps from ps »»

Howto Install Windows Print Drivers onto a Central Samba Share

If you’ve followed my blog for a while you’ve probably noticed that I like to automate just about everything. I can’t stand doing anything manual, at least more than once. So of course when I setup a network printer, I like to have the Windows drivers that go along with each printer available automagically over the network. This technique isn’t glaringly obvious so I thought I’d quickly document how I accomplished it.

Background

This technique requires that you already have both Samba & CUPS servers setup and configured. You should also already have the printer whose drivers we’re going to install configured and working through CUPS. You can read how I did this for the MFC-8480DN printer in this previous post.

Getting Started

First things first, you typically want to grab a copy of the Windows drivers for your particular printer. Remember, in this example I’m using the network capable, Brother MFC-8480DN, that I discussed in this previous post. I downloaded the Windows drivers from the Brother’s website here. Here’s a link the specific driver bundle that I used. Brother calls this bundle the “Add Printer Wizard Driver”. I then set them aside, so I could focus on getting the special Samba share, print$, configured. This is a special share where print drivers for all versions of Windows can be staged, for later consumption by Windows client systems that add this printer.

Samba

adding the print$ share

For my setup, which is a CentOS 5 system, I added the following stanza to my /etc/samba/smb.conf file.

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# /etc/samba/smb.conf
 
[print$]
  comment = Printer Driver Download Area
  path = /etc/samba/drivers
  browseable = yes
  guest ok = yes
  read only = yes
  write list = @samba-printers, root

NOTE: The unpacked driver files that get added to the print$ share will be stored under /etc/samba/drivers on the Samba server. You can put them really anywhere, but I chose to keep them with the Samba config. files.

samba-printers Linux Group

Next, I created a special Linux group that I arbitrarily called samba-printers. Users in this group, in addition to root, will be the only users that have permission to add Windows drivers to the print$ Samba share. I accomplished this by adding the line below to the /etc/group file on the Samba server.

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# /etc/group file on Samba server
 
samba-printers:x:1020:root,user1,user2

The 2 user accounts, user1 & user2, are both Linux accounts as well as Windows accounts. In my home network I typically create them this way to make things like this simpler. If you happen to user different user accounts on Windows vs. Linux you can map the Windows accounts to Linux accounts through the Samba config. file /etc/samba/smbusers.

creating /etc/samba/drivers

Next, I created the directory /etc/samba/drivers and permissioned it with our newly created Linux group using these commands:

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mkdir -m ug+rwx,o-w,g+s /etc/samba/drivers
chgrp samba-printers /etc/samba/drivers


…. Continue reading → Howto Install Windows Print Drivers onto a Central Samba Share »»

[one-liner]: Port Forwarding Using PuTTY

Here’s a little trick that I learned how to do the other day while at work. I’ve done this before using ssh in a linux terminal but hadn’t had the chance to actually do it from a windows box using PuTTY.

Objective

To access a web server (on a remote linux box) which is listening on port 80 through an ssh connection. We want to access the web server through port 10001 on the localhost. This can be accomplished by mapping localhost’s port 10001 to port 80 on the remote host.

Here’s a diagram that attempts to represent what’s going on with the ports, the hosts, and the ssh connection.

ports diagram

ports diagram

Setup

In this scenario we have 2 hosts, the local host (i.e. localhost) and the remote host (homer). Running PuTTY on the localhost, we specify that we want to login to homer as a user on that system, i.e. root, for example. It doesn’t have to be root, this just happens to be the user that I’m using in this example.

putty dialog #1

putty dialog #1

Next in the PuTTY Configuration dialog box, expand the category SSH, and select the category Tunnels. In Tunnels’ configuration, specify the Source port, 10001, and the Destination, homer:80. Then click the Add button.

putty dialog #2

putty dialog #2


…. Continue reading → [one-liner]: Port Forwarding Using PuTTY »»

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