Various tips

See Command list, Windows Tips, File Compression, Linux Tips, Scripts
Send byte to serial port
echo -e "\xFF\x00\x00" > /dev/ttyUSB0
 
See os log
#HP    
tail -100f /var/adm/syslog/syslog.log

#Sun
dmesg
tail -100f /var/adm/messages
 
File system
/etc/group               - user groups
/etc/hosts               - Locally defined hosts (Unix)
/etc/passwd              - passwords
/etc/redhat-release      - [cat] Provide linux base version (Linux RedHat)
/proc/version            - [cat] Provide linux base version (Linux)
/etc/redhat-release      - [cat] Redhat version (Redhat Linux)
/proc/sys/kernel/tainted - [cat] List no open-source modules
/etc/shells              - all available shells
/var/spool/mail/smith    - mail spool location (Linux)
 
vi (most usefull)
Use TERM=vt100
%d - delete all text
:set noautoindent
#same as :set noautonindent on vi, put this on .profile
EXINIT="set noai" ; export EXINIT
 
Mailx
echo "pirlone" | mailx -s "this is subject" aldo@fadalti.com
#Body taken from file
cat attach.html | mailx -s "this is subject" info@fadalti.com aldo@fadalti.com
#Attachments general way
#on Linux you may find uuencode on sharutils 4.2.1
uuencode attach.html attach.html | mailx -s "this is subject" info@fadalti.com aldo@fadalti.com
echo "attachment text" | uuencode cron.txt | mailx -s "culo" a.fadalti@loyalty.co.uk

sending sms
#you need to know what email address is dedicated for sms forwarding
#instead of subject the destination numbers are used
echo "pirloneu" | mailx -s "+393383730860;+393383730860" esisms@fastweb.it

Untested
Send the content of a file
mail aldo@fadalti.com < /myfile

 

See if system is paging out (IBM AIX, Solaris)

>vmstat 3 3

kthr     memory             page              faults        cpu     
----- ----------- ------------------------ ------------ -----------
 r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa 
 8  2 3746722  4767   0   5   6 2039 5616   0 3434 95591 20744 41  8 41 10
16  2 3746727  4203   0   0   0 2904 33175   0 3794 245313 32224 73 12 10  5
15  3 3747141  4258   0   0   0 4609 42401   0 3949 219184 31757 69 15 10  7
Look for po column, if 0 there's no paging

 

Internet IP
The following IP addresses are set aside for local networks, and are not allowed on the Internet: 
10.0.0.0 to 10.255.255.255
172.16.0.0 to 172.31.255.255
192.168.0.0 to 192.168.255.255

 

securecrt /ssh2 db801aol.intranet.fw /l oracle /password pippo

 

Permissions
drwxr----x On a directory you can only list the content