[SOLVED] GNU Parallel facing silent exit and invalid option error

Issue

I tried performing the full installation from: http://git.savannah.gnu.org/cgit/parallel.git/tree/README

The installation was successful. It's working well when installed on Mac OS but on Amazon Linux (RHEL64) I am facing below issues:

1. On running just parallel the command exits silently.

   dev-dsk % parallel
   dev-dsk %
   

2. On running any command even parallel --version gives following error:

   dev-dsk % parallel --version                                               
   parallel: invalid option -- '-'
   parallel [OPTIONS] command -- arguments
       for each argument, run command with argument, in parallel
   parallel [OPTIONS] -- commands
       run specified commands in parallel
   

   Same error with running parallel --gnu.

IMO, there is no conflict with NO conflict with Tollef's parallel of moreutils package as moreutils doesn't exit on my machine.

Please help me understanding how to make GNU Parallel work on RHEL64?

Solution

Not exactly sure why it was not working. In my system there was just one executable named parallel in system path, but still it was not getting detected.

But anyway, I was able to fix it as below:

1. Run whereis parallel. This gives all the paths where executables named parallel is present. For my case there was just one path /usr/local/bin/parallel. Running using this path works just fine.
2. You can add an alias for this in ~/.bashrc or ~/.zshrc file like alias parallel='/usr/local/bin/parallel'

And now parallel works like charm.

dev-dsk % parallel --version         
GNU parallel 20190322
Copyright (C) 2007-2019 Ole Tange and Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
GNU parallel comes with no warranty.

Answered By - bit_cracker007

Answer Checked By - David Goodson (WPSolving Volunteer)