Ubuntu – How to add an alias to a command in terminal

aliasbashrccommand line

By typing a manually specified command in terminal I want to execute some other command.

How could add an alias to a command? Can i do that with the help of the terminal or should I edit some kind of file?

alias new_name='old command'

To create a permanent alias you have to edit the .bashrc file in your home directory.

More info here

More .bashrc files here

Some options:

In your shell script, set a variable, different syntax

petsc='/home/your_user/petsc-3.2-p6/petsc-arch/bin/mpiexec'

$petsc myexecutable

Use a function in your script. Probably better if petsc is complex

function petsc () {
    command 1
    command 2
}

petsc myexecutable

Source your aliases

shopt -s expand_aliases
source /home/your_user/.bashrc

You probably do not want to source your .bashrc, so IMO one of the first 3 would be better.

You need to remove the space before the = in the alias assignment

alias apacheres='/etc/init.d/apache2 restart'