找出符合某些條件的檔案，加以刪除

找出/tmp下，建立時間超過30天，由dsas這個user所建，而且是SAS開頭的檔案，把它刪除掉。
find /tmp -type f -name 'SAS*' -user dsas -ctime +30 -print -exec rm -f '{}' \;

crontab

Crontab command:
crontab –e

Crontab syntax:
A crontab file has five fields for specifying day , date and time followed by the command to be run at that interval.

*     *   *  *   *  command to be executed -     -    -   -  - |     |     |   |    | |     |     |   |    +----- day of week (0 - 6) (Sunday=0) |     |     |   +------- month (1 - 12) |     |     +--------- day of month (1 - 31) |     +----------- hour (0 - 23) +------------- min (0 - 59)

* in the value field above means all legal values as in braces for that column.
The value column can have a * or a list of elements separated by commas. An element is either a number in the ranges shown above or two numbers in the range separated by a hyphen (meaning an inclusive range).
Notes
A. ) Repeat pattern like /2 for every 2 minutes or /10 for every 10 minutes is not supported by all operating systems. If you try to use it and crontab complains it is probably not supported.

B.) The specification of days can be made in two fields: month day and weekday. If both are specified in an entry, they are cumulative meaning both of the entries will get executed .

Crontab Example:
A line in crontab file like below removes the tmp files from /home/someuser/tmp each day at 6:30 PM.

30     18     *     *     *         rm /home/someuser/tmp/*

http://www.adminschoice.com/crontab-quick-reference

How to run windows photo viewer with command line

To start Windows Photo Viewer from command line you would have to use Code:

%SystemRoot%\System32\rundll32.exe "%ProgramFiles%\Windows Photo Viewer\PhotoViewer.dll", ImageView_Fullscreen %1

Find which process has occupied which port

In Linux:
lsof – list open files
The syntax for using "lsof" is:
lsof -i tcp:3480
or
lsof -i udp:3480
if you are interested in port 3480, over the appropriate protocol, TCP or UDP...

In Windows:

C:\>netstat -abno

使用中連線

  協定   本機位址               外部位址               狀態            PID
  TCP    0.0.0.0:80             0.0.0.0:0              LISTENING       1932
 [httpd.exe]
  TCP    0.0.0.0:113            0.0.0.0:0              LISTENING       3580
 [ident.exe]
  TCP    0.0.0.0:135            0.0.0.0:0              LISTENING       800
  RpcSs
 [svchost.exe]
  TCP    0.0.0.0:1025           0.0.0.0:0              LISTENING       472
 [wininit.exe]

In AIX:

netstat -Aa | gret 8080
rmsock xxxxxxxx tcpcb
ps -ef|grep thepid

找出某特定class到底存在哪個jar檔裡

Linux:
find ./ -name "*.jar" |xargs -t -i jar -tvf {}|grep TheClass

Windows + Cygwin
for %f in (*.jar) do jar -tvf %f |grep TheClass