Linux Commands
Linux commands – tcpdump
tcpdump [options] [expression] System administration command. Dump headers and packets of network traffic that match expression. The command continues to capture packets until it receives a SIGTERM or SIGINT signal (usually generated by typing the interrupt character control-C). When finished, it will generate a report on traffic captured, received, or dropped by the kernel. Expressions Create matching [...]
Linux commands – traceroute
traceroute [options] host [packetsize] TCP/IP command. Trace route taken by packets to reach network host. traceroute attempts tracing by launching UDP probe packets with a small TTL (time-to-live), then listening for an ICMP “time exceeded” reply from a gateway. host is the destination hostname or the IP number of the host to reach.packetsize is the packet size in bytes [...]
Linux commands – top
top [options] Provide information (frequently refreshed) about the most CPU-intensive processes currently running. You do not need to include a - before options. Seeps for explanations of the field descriptors. Options -b Run in batch mode; don’t accept command-line input. Useful for sending output to another command or to a file. -c Show command line in [...]
Linux commands – lpstat
lpstat [options] [queues] Show the status of the print queue or queues. With options that take a list argument, omitting the list produces all information for that option. list can be separated by commas or, if enclosed in double quotes, by spaces. For the LPRng print service, lpstat is a frontend to the lpq program. Options -a [list] Show [...]
Linux commands – passwd
passwd [options] [user] Create or change a password associated with a user name. Only the owner or a privileged user may change a password. Owners need not specify theiruser name. Users can change their own passwords. For any other operation, you must be root. Options -d, –delete Delete the password for the user’s account. -f, –force Force the [...]
How to Show network traffic on port 80 – Linux Commands
Please refer the following command to get  network traffic on port 80 under Linux or Unix System # tcpdump not port 80
How to Show top disk users in current dir – Linux Commands
Please refer the following command to get top disk users in current dir  under Linux or Unix System # du -s * | sort -k1,1rn | head
How to Show files by size, biggest last- Linux Commands
Please refer the following command to get  files by size, biggest last  under Linux or Unix System # ls -lSr Example.. [root@pwas2 ~]# ls -lSr total 196212 -rw-r–r– 1 root root 0 Feb 5 2010 test1.txt -rw-r–r– 1 root root 1124 Jul 8 2008 gish -rw-r–r– 1 root root 1574 Jan 24 2008 anaconda-ks.cfg -rw-r–r– 1 [...]
How to test for unreadable blocks on disk- Linux Commands
Please refer the following command to get  Test for unreadable blocks on disk  under Linux or Unix System # badblocks -s /dev/sda
How to Do a read speed test on disk sda – Linux Commands
Please refer the following command to get  read speed test on disk  under Linux or Unix System #hdparm -tT /dev/sda
How to Show info about disk – Linux Commands
Please refer the following command to get  info about disk  under Linux or Unix System [root@pwas2 ~]# hdparm hdparm – get/set hard disk parameters – version v5.7 Usage: hdparm [options] [device] .. Options: -a get/set fs readahead -A set drive read-lookahead flag (0/1) -b get/set bus state (0 == off, 1 == on, 2 == [...]
How to Display SMBIOS/DMI information – Linux Commands
Please refer the following command to get SMBIOS/DMI information under Linux or Unix System # dmidecode -q | less