How to know the command or function for a particular task ?

commandline session $man -k sort alphasort (3) – scan a directory for matching entries apt-sortpkgs (1) – Utility to sort package index files bsearch (3) – binary search of a sorted array bunzip2 (1) – a block-sorting file compressor, v1.0.6 bzip2 (1) – a block-sorting file compressor, v1.0.6 comm (1) – compare two sorted files …

Testing Mail Servers with OpenSSL

commandline session $ openssl s_client -connect pop.mail.yahoo.co.in:995 CONNECTED(00000003) depth=1 C = US, O = DigiCert Inc, OU = www.digicert.com, CN = DigiCert High Assurance CA-3 verify error:num=20:unable to get local issuer certificate verify return:0 — Certificate chain 0 s:/C=US/ST=CA/L=Sunnyvale/O=Yahoo! Inc./CN=legacy.pop.mail.yahoo.com i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance CA-3 1 s:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance CA-3 i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance …

geoiplookup – look up country using IP Address or hostname

commandline session $nslookup beautifulwork.org Server: 192.168.0.1 Address: 192.168.0.1#53 Non-authoritative answer: Name: beautifulwork.org Address: 80.79.116.205 $geoiplookup 80.79.116.205 GeoIP Country Edition: EE, Estonia $nslookup www.trueangle.org Server: 192.168.0.1 Address: 192.168.0.1#53 Non-authoritative answer: www.trueangle.org canonical name = trueangle.org. Name: trueangle.org Address: 80.79.116.205 $nslookup www.gnu.org Server: 192.168.0.1 Address: 192.168.0.1#53 Non-authoritative answer: www.gnu.org canonical name = wildebeest.gnu.org. Name: wildebeest.gnu.org Address: 208.118.235.148 …

tshark – Dump and analyze network traffic

ABOUT tshark TShark is a command-line network traffic analyzer that enables you to capture packet data from a live network or read packets from a previously saved capture file by either printing a decoded form of those packets to the standard output or by writing the packets to a file. Without any options, TShark works …

ssh-keygen — authentication key generation, management and conversion

ahiliation@pluto:~$ ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/home/ahiliation/.ssh/id_rsa): Created directory ‘/home/ahiliation/.ssh’. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/ahiliation/.ssh/id_rsa. Your public key has been saved in /home/ahiliation/.ssh/id_rsa.pub. The key fingerprint is: 70:7f:99:30:63:19:1e:ea:0f:af:ce:7d:dd:e5:55:9a ahiliation@pluto.infoclub.in The key’s randomart image is: …

WSU pTop is a simple and effcient process-level power profiling tool

$ls conf doc makefile objects.mk sources.mk src $make all cc -c -o src/avltree.o src/avltree.c In file included from src/avltree.c:12:0: src/eperf.h: In function ‘sys_perf_event_open’: src/eperf.h:32:17: error: ‘__NR_perf_counter_open’ undeclared (first use in this function) return syscall(__NR_perf_counter_open, attr, pid, cpu, group_fd, flags); ^ src/eperf.h:32:17: note: each undeclared identifier is reported only once for each function it appears in …

gnome-shell – Graphical shell for the GNOME desktop

$gnome-shell org.gnome.Shell already exists on bus and –replace not specified $gnome-shell –replace Window manager warning: Log level 16: Attempt to add property Gjs_MonitorConstraint::primary after class was initialised Window manager warning: Log level 16: Attempt to add property Gjs_MonitorConstraint::index after class was initialised Window manager warning: Log level 16: Error converting selection Window manager warning: Log …