AIX-to-Linux Quick Start Comparison

Modified from a more-complete page.

Directory Mappings AIX RedHat Linux
Root File System /        /dev/hd4 /      /dev/sda2 if SCSI
       /dev/hda2 if IDE
Home Directories /home    /dev/hd1 /home is in Root File System
O.S. Executables /usr     /dev/hd2 /usr is in Root File System
Temporary Space /tmp     /dev/hd3 /tmp is in Root File System
System Variable Data /var     /dev/hd9var /var is in Root File System
Boot          /dev/hd5 /boot    /dev/sda1 if SCSI
         /dev/hda1 if IDE
Paging Logical Volume type="paging" Partition Id=82="Linux swap"

See also the Filesystem Hierachy Standard (FHS) for a fuller discussion of the "proper" UNIX file system hierarchy.

Linux has three sets of apparently duplicate directories; /bin & /usr/bin, /sbin & /usr/sbin, and /lib & /usr/lib. This can be a source of confusion. Under AIX for example, ksh is the default shell and it's normal to see #!/usr/bin/ksh in the first line of a ksh script. Under Linux, bash (the Bourne-Again Shell) is the default shell and ksh is NOT in /usr/bin/ksh, leading one to believe Linux does not have ksh. Not true. Under Linux, ksh is at /bin/ksh. (Actually, since /bin is a link to /usr/bin under AIX, ksh is also at /bin/ksh, so to make bilinugual scripts, #!/bin/ksh is best.)

The reason for these apparently duplicate directories is, in the initial boot phases or when Linux boots into single-user mode (which is the same thing), only the root file system is mounted. It's true that by default, /usr is in the root file system, but it may not be. It might be configured in its own partition or even NFS mounted from another machine in R/O mode. Given this, everything needed to boot Linux or will be needed to repair a broken system, needs to be in the root file system. Yet to keep the root file system as small as possible, all non-essential files are kept under /usr.

This is also why they say that those 5 directories (/bin, /sbin, /etc, /dev, and /lib) must be in the root partition.

User Accounts AIX RedHat Linux
Password Files /etc/passwd
Allow/Deny root's Remote telnet Login rlogin=true in /etc/security/user stanza Comment out securetty line in /etc/pam.d/login
Recover root's Password Boot from CD or Tape,
   Start Limited Shell
   getrootfs hdisk0
   vi /etc/security/passwd
At grub boot loader screen,
   press "e" to edit,
   select "kernel" line
   press "e" to edit,
   Add " s" at end of line
   press <Enter> to accept changes,
   press "b" to boot,
   at shell prompt, passwd root
Create new user mkuser useradd
Delete user rmuser userdel
Default User Group staff=Group ID 1 The same as their userid, both name and number. E.G. User Name=jasper, User ID=10167, Group Name=jasper, Group ID=10167

General Commands AIX RedHat Linux
Absolute Path tar tar cvf foo.tar /etc/passwd tar Pcvf foo.tar /etc/passwd
ping Broadcast Address ping -c 1 ping -b -c 1
Admin Helpers smit or smitty 41 redhat-config-* programs in /usr/sbin & /usr/bin
Performance Monitor top
System Activity Reporter sar sar
I/O Statistics iostat iostat
Boot-Time Error Log alog -o -t boot dmesg
Display Swap Size lsps -a free

Printers AIX RedHat Linux
Printer Queues /etc/qconfig /var/spool/lpd/lp/*
Control Print Server Daemon startsrc -s lpd
stopsrc  -s lpd
lssrc    -s lpd
service cups start
service cups stop
service cups status
Submit Print Jobs enq
LP Statistics enq -A
Remove Print Jobs cancel
enq -x
Add Printer Queue smit mkpq redhat-config-printer
Remove Printer Queue smit rmpq  
Default Printer First Stanza in /etc/qconfig
export LPDEST="pq"

TCP/IP AIX RedHat Linux
Network IP Configuration lsattr -E -l inet0 /etc/sysconfig/network-scripts/ifcfg-eth*
Name Service Switch /etc/netsvc.conf /etc/nsswitch.conf
Network Parameters no -a sysctl -a | grep net
Secondary IP Address ifconfig en0 alias w.x.y.z modprobe ip_alias
ifconfig eth0:1 w.x.y.z
Login Prompt/Herald /etc/security/login.cfg /etc/issue

System Files AIX RedHat Linux
NFS Client Mounted Directories /etc/xtab /var/lib/nfs/xtab
Max File System Size 128 GB 2 TB
Max File Size 64 GB    2 GB   (512-byte block size)
8192 GB   (8-KB block size)

LVM Commands AIX RedHat Linux
Filesystem Table /etc/filesystems /etc/fstab
Device Listing lsdev -C cat /proc/devices
Disk Information bootinfo -s hdisk# cat /proc/scsi/scsi0/sda/model
LVM Concepts Partition Logical Extents
  Volume Logical Volume
Journal File System Type jfs ext3
Default Volume Group /dev/rootvg None
Display Volume Group lsvg -l rootvg vgdisplay -v
Modify Physical Volume chpv pvchange
Prepare Physical Disk mkdev -c disk -l hdisk# pvcreate
List Physical Volume lspv pvdisplay
Remove disk from volume group reducevg vgreduce
Move logical volumes to another physical volumes migratepv pvmove
Create volume group mkvg vgcreate
Remove Volume Group varyoffvg
Volume Group Availability chvg
Restore Volume Group importvg vgcfgrestore
Export/Import Volume Group exportvg/importvg vgexport/vgimport
List Volume Groups lsvg vgscan
Change Logical Volume Characteristics chlv lvchange
List Logical Volumes lslv lvdisplay
Make Logical Volume mklv lvcreate
Extend Logical Volume extendlv lvextend
Reduce Logical Volume AIX Reduce LV Procedure lvreduce
Remove Logical Volume rmlv lvremove
Prepare Boot Volumes bootlist -m normal grub-install /dev/sda2 if SCSI
grub-install /dev/hda2 if IDE
Extend File System chfs -a size=# fs-name
(# is 512-byte blocks)
Reduce/Split Mirrors rmlvcopy lvsplit
Merge Mirrors   lvmerge
Create Mirrors mklv -c 2  
Add Mirrors mklvcopy lv 2  
Create Striped Volumes mklv -u 3 -S 64K lvcreate -i 3 -I 64
System Recovery Tape mksysb -i /dev/rmt0  
Backup savevg -i rootvg tar cvf /dev/rst0 /
Restore restvg tar xvf /dev/rst0

Miscellaneous Commands AIX RedHat Linux
Startup script /etc/rc /etc/rc.d/rc
Kernel /usr/lib/boot/unix_up /boot/vmlinuz (compressed)
/boot/vmlinux (uncompressed)
Kernel Parameters lsattr -E -l sys0
no -a
sysctl -a
Reconfigure the Kernel chdev -l sys0 -a cd /usr/src/linux
make mrproper
make menuconfig
make dep
make clean
make bzImage
make install
make modules
make modules_install
cp arch/i386/boot/bzImage /boot/vmlinuz-2.2.16
cd /boot
mv initrd-2.4.21-20.ELsmp
mkinitrd initrd-2.4.21-20.ELsmp $(uname -r)

vi /boot/grub/grub.conf
List modules genkex lsmod
Load module   insmod
Unload module   rmmod
Initialize System install_assist netconf
Physical RAM bootinfo -r free
Kernel Bits bootinfo -K getconf WORD_BIT
Crash Utility crash lcrash
Trace System Calls syscalls strace
OS Level oslevel uname -r
Run Level who -r runlevel
Tape Control tctl mt
Core Dump Files /var/adm/ras  
Timezone Management /etc/environment
NTP Daemon /etc/ntp.conf
startsrc -s xntpd
stopsrc -s xntpd
lssrc -s xntpd
service xntpd start
service ntpd stop
service ntpd status

Software AIX RedHat Linux
Install Software installp -a rpm -i package
Uninstall Software installp -u rpm -e package
List Installed Software lslpp -L all rpm -qa
Verify Installed Software lppchk -v rpm -V package
List Files lslpp -f fileset rpm -ql package
List Installed Patches instfix -i  
Package Owner lslpp -w path rpm -qf file
SW Directory /usr/lpp /var/lib/rpm
Rescan SCSI Bus cfgmgr echo "scsi add-single-device 0 1 2 3" > /proc/scsi/scsi
will reprobe for a single device only on Card 0, Channel 1, Device 2, Lun 3, and add it if it is found

Devices AIX RedHat Linux
Install Devices cfgmgr -v /dev/MAKEDEV
Remove Device rmdev -l  
Device Drivers lscfg  
CPU lsdev -Cc processor cat /proc/cpuinfo
List Terminal lsdev -Cc tty  
Diagnostics diag lspci
Whole Disk /dev/hdisk# /dev/sda
CDROM /dev/cd0 /dev/cdrom
CDROM File System Type cdrfs iso9660
Rewinding Tape Drive /dev/rmt0 /dev/rst0      { c 9 0}
Non-rewinding Tape Drive /dev/rmt0.1 /dev/nrst0      { c 9 128 }
Floppy Drive /dev/rfd0 /dev/fd0

AFS AIX RedHat Linux
Code Source IBM Transarc's Lab
AFS Cache
Should be defined as its own file system before installing AFS. 100MB is minimum. 1GB is better. Same.
Install Directions cd /tmp
ftp jasper
   cd /afs/d/software/base/AFS_3.6
   get afsclient-42.tar
chmod +x
./ afsclient-42.tar
rm afsclient-42.tar
mkdir /tmp/afs
cd /tmp/afs
scp -p jasper@jasper:/afs/d/software/base/linux/openafs-1.2.11/* .
rpm -ivh *rpm
vi /usr/vice/etc/cacheinfo and set the cache size to 95% of the number of 1K blocks of /usr/vice/cache. 95% of 1GB (my standard), is 953850.
vi /usr/vice/etc/ThisCell
set the cell name to
vi /usr/vice/etc/CellServDB
replace all existing lines with
> # Thomson-Delphion
To start AFS, service afs start
To allow AFS-authenticated logins, ftp's, etc,
cd /etc/pam.d
cp -p system-auth system-auth.Before.AFS
cp -p --reply=yes /tmp/afs/system-auth system-auth
rm -rf /tmp/afs
(fs sysname)
rs_aix42 i386_linux24
Delphion-Standard Links /local -> /afs/d/@sys/local
/u -> /afs/d/u
/usr/afsws -> /afs/d/@sys/usr/afsws
/local -> /afs/d/@sys/local
/u -> /afs/d/u

Other References AIX RedHat Linux
Online Manual AIX 4.3 Books Linux Documentation Project
Technical Support RS/6000 TechSupport Red Hat support
Phone Number 1-800-CALL-AIX 1-888-REDHAT1
Free Software Bull Linux Software Map
Certification RHCT & RHCE