Installing nmap in Ubuntu

I want to using nmap in my Ubuntu server but I found that nmap is not installed yet.
root@ubuntu:~# nmap
The program 'nmap' is currently not installed. You can install it by typing:

So, to install nmap just type the below command. It is extremely simple and easy :)
type this command : apt-get install nmap
-bash: nmap: command not found
root@ubuntu:~# apt-get install nmap
** nmap will be installed and the below process will be shown
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
nmap
0 upgraded, 1 newly installed, 0 to remove and 46 not upgraded.
Need to get 1080kB of archives.
After this operation, 3789kB of additional disk space will be used.
Get:1 http://my.archive.ubuntu.com intrepid/main nmap 4.62-1ubuntu1 [1080kB]
Fetched 1080kB in 20s (52.4kB/s)
Selecting previously deselected package nmap.
(Reading database ... 53517 files and directories currently installed.)
Unpacking nmap (from .../nmap_4.62-1ubuntu1_amd64.deb) ...
Processing triggers for man-db ...
Setting up nmap (4.62-1ubuntu1) ...

taddaaaaaaa...!!!! Nmap is installed..Yeaaaaa
root@ubuntu:~# nmap
Nmap 4.62 ( http://nmap.org )
Usage: nmap [Scan Type(s)] [Options] {target specification}
TARGET SPECIFICATION:
Can pass hostnames, IP addresses, networks, etc.
Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.0-255.1-254
-iL : Input from list of hosts/networks
-iR : Choose random targets
--exclude : Exclude hosts/networks
--excludefile : Exclude list from file
HOST DISCOVERY:
-sL: List Scan - simply list targets to scan
-sP: Ping Scan - go no further than determining if host is online
-PN: Treat all hosts as online -- skip host discovery
-PS/PA/PU [portlist]: TCP SYN/ACK or UDP discovery to given ports
-PE/PP/PM: ICMP echo, timestamp, and netmask request discovery probes
-PO [protocol list]: IP Protocol Ping
-n/-R: Never do DNS resolution/Always resolve [default: sometimes]
--dns-servers : Specify custom DNS servers
--system-dns: Use OS's DNS resolver
SCAN TECHNIQUES:
-sS/sT/sA/sW/sM: TCP SYN/Connect()/ACK/Window/Maimon scans
-sU: UDP Scan
-sN/sF/sX: TCP Null, FIN, and Xmas scans
--scanflags : Customize TCP scan flags
-sI : Idle scan
-sO: IP protocol scan
-b : FTP bounce scan
--traceroute: Trace hop path to each host
--reason: Display the reason a port is in a particular state
PORT SPECIFICATION AND SCAN ORDER:
-p : Only scan specified ports
Ex: -p22; -p1-65535; -p U:53,111,137,T:21-25,80,139,8080
-F: Fast mode - Scan fewer ports than the default scan
-r: Scan ports consecutively - don't randomize
--top-ports : Scan most common ports
--port-ratio : Scan ports more common than
SERVICE/VERSION DETECTION:
-sV: Probe open ports to determine service/version info
--version-intensity : Set from 0 (light) to 9 (try all probes)
--version-light: Limit to most likely probes (intensity 2)
--version-all: Try every single probe (intensity 9)
--version-trace: Show detailed version scan activity (for debugging)
SCRIPT SCAN:
-sC: equivalent to --script=safe,intrusive
--script=: is a comma separated list of
directories, script-files or script-categories
--script-args=: provide arguments to scripts
--script-trace: Show all data sent and received
--script-updatedb: Update the script database.
OS DETECTION:
-O: Enable OS detection
--osscan-limit: Limit OS detection to promising targets
--osscan-guess: Guess OS more aggressively
TIMING AND PERFORMANCE:
Options which take are in milliseconds, unless you append 's'
(seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30m).
-T[0-5]: Set timing template (higher is faster)
--min-hostgroup/max-hostgroup : Parallel host scan group sizes
--min-parallelism/max-parallelism : Probe parallelization
--min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout : Specifies
probe round trip time.
--max-retries : Caps number of port scan probe retransmissions.
--host-timeout : Give up on target after this long
--scan-delay/--max-scan-delay : Adjust delay between probes
--min-rate : Send packets no slower than per second
FIREWALL/IDS EVASION AND SPOOFING:
-f; --mtu : fragment packets (optionally w/given MTU)
-D : Cloak a scan with decoys
-S : Spoof source address
-e : Use specified interface
-g/--source-port : Use given port number
--data-length : Append random data to sent packets
--ip-options : Send packets with specified ip options
--ttl : Set IP time-to-live field
--spoof-mac : Spoof your MAC address
--badsum: Send packets with a bogus TCP/UDP checksum
OUTPUT:
-oN/-oX/-oS/-oG : Output scan in normal, XML, s| and Grepable format, respectively, to the given filename.
-oA : Output in the three major formats at once
-v: Increase verbosity level (use twice or more for greater effect)
-d[level]: Set or increase debugging level (Up to 9 is meaningful)
--open: Only show open (or possibly open) ports
--packet-trace: Show all packets sent and received
--iflist: Print host interfaces and routes (for debugging)
--log-errors: Log errors/warnings to the normal-format output file
--append-output: Append to rather than clobber specified output files
--resume : Resume an aborted scan
--stylesheet : XSL stylesheet to transform XML output to HTML
--webxml: Reference stylesheet from Insecure.Org for more portable XML
--no-stylesheet: Prevent associating of XSL stylesheet w/XML output
MISC:
-6: Enable IPv6 scanning
-A: Enables OS detection and Version detection, Script scanning and Traceroute
--datadir : Specify custom Nmap data file location
--send-eth/--send-ip: Send using raw ethernet frames or IP packets
--privileged: Assume that the user is fully privileged
--unprivileged: Assume the user lacks raw socket privileges
-V: Print version number
-h: Print this help summary page.
EXAMPLES:
nmap -v -A scanme.nmap.org
nmap -v -sP 192.168.0.0/16 10.0.0.0/8
nmap -v -iR 10000 -PN -p 80
SEE THE MAN PAGE FOR MANY MORE OPTIONS, DESCRIPTIONS, AND EXAMPLES
root@ubuntu:~#