Creating an alias for Python in bash/zsh

aliasbashpythonterminalzsh

I have often seen people recommending to setup an alias in one's .bash_profile or .zshrc along the lines of

alias python='python3'

This seems like a convenient idea, however, as far as I understand, python2 is still installed for compatibility reasons, so won't creating such an alias break certain things?

Best Answer

From man bash

Aliases  are not expanded when the shell is not interactive, unless the
expand_aliases shell option is set using shopt (see the description  of
shopt under SHELL BUILTIN COMMANDS below).

So unless you explicitly set an option, aliases aren't expanded in scripts and any reference to python will call the binary directly. For interactive use it's probably best to call python2 directly if you rely on pre-3 syntax/functionality.

PS: AFAIK it's the same for zsh.

Related Solutions

macOS Bash – How to Use ‘Alias’ in Bash Script

Aliases aren't interpreted within shell scripts. From bash(1):

Aliases are not expanded when the shell is not interactive, unless the expand_aliases
shell option is set using shopt)

So the script still calls the standard readlink which doesn't know about --help.

Instead of setting expand_aliases (which you have to remember to do so on each system and which may lead to unexpected side-effects in other scripts) I would recommend to use functions instead:

function my_readlink() {
    greadlink "$@"
}
my_readlink --help

Automator – Running zsh Alias via Automator

The solution is to source the file dependencies you need inside the automator script.

Example if you added all of your scripts to ~/.zshrc

source ~/.zshrc
deploy

You can debug things easier by doing which deploy to check to see if that script is accessible.

Best Answer

Related Solutions

macOS Bash – How to Use ‘Alias’ in Bash Script

Automator – Running zsh Alias via Automator

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