Since newer versions of Ubuntu like 20, you will find there is no longer dynagen and that the dynamips provided is faulty and will segfault each time:
Cisco Router Simulation Platform (version 0.2.14-amd64/Linux stable)
Copyright (c) 2005-2011 Christophe Fillot.
Build date: Apr 3 2018 12:20:29
Local UUID: 3c1c0b7f-2fab-4fda-b40b-74841d1bcfe0
Instance ID set to 1.
netio_tap_create: unable to open TAP device tap1 (No such fi........
Perhaps you've just seen this in the bash prompt:
-bash-4.1#
Instead of the expected user@hostname#
It is probably because you are missing .bash_profile or .bashrc in your home directory
Check for yourself:
ls -al ~/|grep -E ".bash_profile|.bashrc"
-rw-r--r--. 1 root root&nbs........
Usually this is because when you created your user you added a user but didn't create their home directory and/or for some reason your .bashrc and .bash_profile in ~ (home) is broken/missing.
In your home just create the following files with the following content to solve it:
.bashrc and .bash_profile.
To apply it just relogin/start a new bash session
# .bash_profile
# Get the aliases and funct........
This through me for a loop when I would do a cp -rf or mv -f nothing would get overwritten even if piping y or yes to the command.
Type alias and you'll see why:
alias cp='cp -i'
alias l.='ls -d .* --color=auto'
alias ll='ls -l --color=auto'
alias ls='ls --color=auto'
alias mv='mv -i'
alias rm='rm -i'
The -i is a safeguard against messing things up but however does mess things up worse when you know what........