DBA Hacker’s guide to Solaris

1.    Handy Solaris commands     HW config, swap, patches etc.
2.    Real-time performance monitoring     vmstat, iostat, mpstat etc.
3.    Unix Commands     find, awk, sed, grep etc.
4.    vi editor commands     the 22 most useful vi commands
5.    Unix file permissions explained      sounds basic, but you may learn something new here!
6.    The Solaris Name Service explained     how hostname and username lookups work

1. Handy Solaris commands

• show hardware config (memory, CPUs etc) :

  /usr/platform/sun4u/sbin/prtdiag -v |more
  /usr/sbin/psrinfo
• show kernel settings:

  /usr/sbin/sysdef |more
  more /etc/system

• show list of Solaris patches:

  showrev -p |more

• show software installed:

  pkginfo |more

• check swap space:

  /usr/sbin/swap -s

• check system load average: an uptime more than double the number of CPUs is getting a bit busy

  uptime

• top CPU users:

  /usr/ucb/ps uax |head

• top memory users:

  /usr/ucb/ps vax |head

• check disk space:

  df -k   (shows all mounted filesystems -including NFS etc)
  df -lk   (shows only local filesystems)
  df -k -Fufs (shows only local Sun UFS filesystems (normal hard disks)
  df -k .   (show just the filesystem you are currently in)

2. Real-time performance monitoring:

• at - run a command or script once in the future

bash$ at 0815 tomorrow
at> rm $HOME/zxc
at> (type Control-D)
commands will be executed using /usr/bin/bash
job 984032100.a at Thu Mar 8 06:15:00 2001

• awk
• cron

crontab -l  to see your crontab
crontab -e   to edit it (NB but first do EDITOR=vi (or EDITOR=emacs) ; export EDITOR )
Remember fields are : minute hour day month day_of_week (0=Sun)
0-59 0-23 1-31 1-12 0-6
e.g. run a script only on Tuesdays to Fridays, at 10:12 am, 3:12pm, 4:12pm and 5:12pm
12 10,15-17 * * 2-5/home/oracle/bin/script

• du
  -show disk space usage
  du -k  -show disk usage in kB in all subdirectories below the current one
  du -sk   -show just the total of everything below the current dir
  du -sk *   -show individual totals for each file or directory in the current dir

• find

find things you can’t remember the exact name of :
  find /usr/lib -name "*socket*"
find big files (more than 20000 blocks, ie about 10MB )
  find . -size +20000
find files or directories modified in last day
  find . -mtime -1
find files not accessed (read) in 45 days
  find /tmp -atime +45
Add -ls to the end of any of the above commands to see a full ls -l listing of the files found.


You can combine multiple options , e.g look for which big files have filled up a filesystem recently
  find . -size +20000 -mtime -1 -ls
Or combine options using an "OR" syntax, e.g. find files which were modified either less than 1 week ago or more than 2 weeks ago
  find . \( -mtime +14 -o -mtime -7 \) -ls
You can send the ouput of find to another command : the xargs command is ideal for this: e.g. interactively delete all core files under your $HOME
  find ~ -type f -name core |xargs rm -i
or look for a particular word in all your .c files:
  find . -name "*.c" |xargs grep -l libsocket


• grep   and its more flexible and faster cousins egrep and fgrep

Search for either of two strings in all log files:
  egrep "error|PROBLEM" *log
case-insensitive search
  fgrep -i error *log   (will find Error, ERROR, etc.)
just see the filenames where the search text was found
  grep -l error *log

• sort

-n sorts by number instead of alphabetically
e.g. cd /export/home; du -sk * | sort -nr lists who is using most space in their home directory


• tar


e.g. to copy a directory tree, preserving symlinks:
  cd fromdir; tar cf - . | (cd todir; tar xpf -)

• tr    translate characters

convert lower-case to upper:
  cat myfile | tr [a-z] [A-Z]
change colons to newlines:
  tr : "\n" < myfile > newfile

• who  show who is currently logged on and where from
  
• w  show what people are doing
  

other useful Unix commands for you to check out:

The basic vi commands:

i	insert before current character	a	append after current char
I	insert at beginning of line	A	append after end of line
x	delete current character	X	backspace-delete (deletes char to left)
dd	delete current line
22dd	delete 22 lines	u	undo the last thing you did
p	paste those 22 lines below the current line
12yy	copy 12 lines into the ‘clipboard’ for later pasting
<Esc>	to get out of editing (insert/append) mode
:wq	to save ('write') and quit (:q! to quit without writing)

vi moving-around Timesavers:

using h,j,k,l to move left,down,up and right is quicker than using the arrow keys (once you get used to it!).

w	move one word forward	b	move back a word	e	go to end of word
Ctl-F	move Forward a whole page	Ctl-B	move Back a page
0	(zero) go to beginning of line			$	go to end of line
:242	go to line 242	Ctl-G	see what line you are on

vi modifying things:

cw	change word	3cw	change 3 words	C	change to end-of-line
dw	delete word			D	delete to end-of-line
cc	replace current line with what you type next
r	replace one character	R	endless replace (like over-typing)
o	open/add a new line below the current one			O	open new line above current one
xp	swap two characters (e.g. when you make a typo)
/bob	search forward for 'bob'	n	repeat previous search	?	search backwards

Probably the handiest vi command:
  .  (dot) -repeat your last command

useful extra vi commands:
  ~    swap case of current character (capitalize or lower-case)
  Ctl-L    re-draw the screen (e.g when something from a background process writes to your screen and messes up your vi window)
  :set nu    show line numbers (:set nonu to remove line numbers)
  :set list    show hidden characters, line endings etc. (: set nolist)

Global replace:
     :%s/old/new/g  (% means all lines)
or     :g/old/s//new/g
or     :%s/old/new/gc  (c is to confirm each replacement, type ‘y’ to accept)

5. Unix file permissions

What you may not know is that whether someone can delete that file is not determined by the file permissions, but by the permissions of the directory the file is in :
  bash$ ls -al
  total 598
  drwxrwxr-x  3 robins  devteam 512 Mar 8 12:02 .
  drwxr-xr-x 24 root    wheel  1024 Mar 8 12:02 ..
  -rwxr-xr--  1 robins  devteam 180 Mar 8 13:50 instbb
In this case the directory (.) is group writeable, which means anyone in the group devteam can delete the file instbb. Although they can’t modify it, they could copy it to a new file in that directory, modify it, then delete the original and rename the new file as instbb. So the file isn’t as secure as it may appear..

6. Solaris Name services

Solaris provides a mechanism for getting hostnames and usernames etc from several sources (e.g DNS, NIS, or the traditional /etc/hosts file) : the file /etc/nsswitch.conf , which may contain
  hosts: files dns
this means that when you try to access a remote host by name (e.g. ping neptune) it will look for neptune first in /etc/hosts, then do an lookup in DNS (nslookup using the server specified in /etc/resolv.conf)

Similarly for usernames, you may have
  passwd: files nis
So when you run a command which refers to a username (e.g. cd ~oracle ) , it first looks in /etc/passwd then does a lookup in NIS (ypmatch oracle passwd).