AIX Commands you cannot live without it. part 1

Introduction

As you know, AIX® has a vast array of commands that enable you to do a multitude of tasks. Depending on what you need to accomplish, you use only a certain subset of these commands. These subsets differ from user to user and from need to need. However, there are a few core commands that you commonly use. You need these commands either to answer your own questions or to provide answers to the queries of the support professionals.

In this article, I'll discuss some of these core commands. The intent is to provide a list that you can use as a ready reference. While the behavior of these commands should be identical in all releases of AIX, they have been only tested under AIX 5.3.

Note:
The bootinfo command discussed in the following paragraphs is NOT a user-level command and is NOT supported in AIX 4.2 or later.

Commands

Kernel

How would I know if I am running a 32-bit kernel or 64-bit kernel?

To display if the kernel is 32-bit enabled or 64-bit enabled, type:
bootinfo -K

How do I know if I am running a uniprocessor kernel or a multiprocessor kernel?

/unix is a symbolic link to the booted kernel. To find out what kernel mode is running, enter ls -l /unix and see what file /unix it links to. The following are the three possible outputs from the ls -l /unix command and their corresponding kernels:

/unix -> /usr/lib/boot/unix_up # 32 bit uniprocessor kernel /unix -> /usr/lib/boot/unix_mp # 32 bit multiprocessor kernel/unix -> /usr/lib/boot/unix_64 # 64 bit multiprocessor kernel

Note:
AIX 5L Version 5.3 does not support a uniprocessor kernel.

How can I change from one kernel mode to another?

During the installation process, one of the kernels, appropriate for the AIX version and the hardware in operation, is enabled by default. Let us use the method from the previous question and assume the 32-bit kernel is enabled. Let us also assume that you want to boot it up in the 64-bit kernel mode. This can be done by executing the following commands in sequence:

#ln -sf /usr/lib/boot/unix_64 /unix
#/usr/lib/boot/unix bosboot -ad /dev/hdiskxx
#shutdown -r

The /dev/hdiskxx directory is where the boot logical volume /dev/hd5 is located. To find out what xx is in hdiskxx, run the following command:

#lslv -m hd5

Note:
In AIX 5.2, the 32-bit kernel is installed by default. In AIX 5.3, the 64-bit kernel is installed on 64-bit hardware and the 32-bit kernel is installed on 32-bit hardware by default.

Hardware

How would I know if my machine is capable of running AIX 5L Version 5.3?

AIX 5L Version 5.3 runs on all currently supported CHRP (Common Hardware Reference Platform)-based POWER hardware.

How would I know if my machine is CHRP-based?

Run the prtconf command. If it's a CHRP machine, the string chrp appears on the Model Architecture line.

How would I know if my System p machine (hardware) is 32-bit or 64-bit?

To display if the hardware is 32-bit or 64-bit, type:

#bootinfo -y

How much real memory does my machine have?

To display real memory in kilobytes (KB), type one of the following:

#bootinfo -r

#lsattr -El sys0 -a realmem

Can my machine run the 64-bit kernel?

64-bit hardware is required to run the 64-bit kernel.

What are the values of attributes for devices in my system?

To list the current values of the attributes for the tape device, rmt0, type:

#lsattr -l rmt0 -E

To list the default values of the attributes for the tape device, rmt0, type:

#lsattr -l rmt0 -D

To list the possible values of the login attribute for the TTY device, tty0, type:

#lsattr -l tty0 -a login -R

To display system level attributes, type:

#lsattr -E -l sys0

How many processors does my system have?

To display the number of processors on your system, type:

#lscfg | grep proc

How many hard disks does my system have and which ones are in use?

To display the number of hard disks on your system, type:

#lspv

How do I list information about a specific physical volume?

To find details about hdisk1, for example, run the following command:

#lspv hdisk1

How do I get a detailed configuration of my system?

Type the following:

#lscfg

The following options provide specific information:
-p

Displays platform-specific device information. The flag is applicable to AIX 4.2.1 or later.
-v
Displays the VPD (Vital Product Database) found in the customized VPD object class.

For example, to display details about the tape drive, rmt0, type:

lscfg -vl rmt0

You can obtain very similar information by running the prtconf command.

How do I find out the chip type, system name, node name, model number, and so forth?

The uname command provides details about your system.

#uname -p
Displays the chip type of the system. For example, PowerPC.

#uname -r
Displays the release number of the operating system.

#uname -s
Displays the system name. For example, AIX.

#uname -n
Displays the name of the node.

#uname -a
Displays the system name, nodename, version, machine ID.

#uname -M
Displays the system model name. For example, IBM, 9114-275.

#uname -v
Displays the operating system version.

#uname -m
Displays the machine ID number of the hardware running the system.

#uname -u
Displays the system ID number.

AIX

What version, release, and maintenance level of AIX is running on my system?

Type one of the following:

#oslevel –r

#lslpp -h bos.rte

How can I determine which fileset updates are missing from a particular AIX level?

To determine which fileset updates are missing from 5300-04, for example, run the following command:

#oslevel -rl 5300-04

What SP (Service Pack) is installed on my system?

To see which SP is currently installed on the system, run the oslevel -s command. Sample output for an AIX 5L Version 5.3 system, with TL4, and SP2 installed would be:

#oslevel –s5300-04-02

Is a CSP (Concluding Service Pack) installed on my system?

To see if a CSP is currently installed on the system, run the oslevel -s command. Sample output for an AIX 5L Version 5.3 system, with TL3, and CSP installed would be:

#oslevel –s5300-03-CSP

How do I create a file system?

The following command will create, within volume group testvg, a jfs file system of 10MB with mounting point /fs1:

#crfs -v jfs -g testvg -a size=10M -m /fs1

The following command will create, within volume group testvg, a jfs2 file system of 10MB with mounting point /fs2 and having read only permissions:

#crfs -v jfs2 -g testvg -a size=10M -p ro -m /fs2

How do I change the size of a file system?

To increase the /usr file system size by 1000000 512-byte blocks, type:

#chfs -a size=+1000000 /usr

Note:
In AIX 5.3, the size of a JFS2 file system can be shrunk as well.

How do I mount a CD?

Type the following:

#mount -V cdrfs -o ro /dev/cd0 /cdrom

How do I mount a file system?

The following command will mount file system /dev/fslv02 on the /test directory:

#mount /dev/fslv02 /test

How do I mount all default file systems (all standard file systems in the /etc/filesystems file marked by the mount=true attribute)?

The following command will mount all such file systems:

#mount {-a|all}

How do I unmount a file system?

Type the following command to unmount /test file system:

#umount /test

How do I display mounted file systems?

Type the following command to display information about all currently mounted file systems:

#mount

How do I remove a file system?

Type the following command to remove the /test file system:

#rmfs /test