gnuplot package not found

Question

I have installed Ubuntu 14.04.1. I tried installing Gnupolot, gfortran using sudo ap get install, but the terminal shows 'unable to locate package gnuplot-x11' and 'The following package cannot be authenticated'.

Answer 1

For gnuplot, do you have universe repository enabled? Should be there:

[romano:~] % apt-cache policy gnuplot-x11
gnuplot-x11:
  Installed: 4.6.4-2
  Candidate: 4.6.4-2
  Version table:
 *** 4.6.4-2 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
        100 /var/lib/dpkg/status

gfortran, instead, is in main; should be installed without any problem:

[romano:~] % apt-cache policy gfortran   
gfortran:
  Installed: (none)
  Candidate: 4:4.8.2-1ubuntu6
  Version table:
     4:4.8.2-1ubuntu6 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

...so please edit your question to report the exact errors you have.