How to pass a conditional string to command in bash

Question

I'm trying to alias my php command by executing it with an argument depending on if a file with my remote host IP is existant, without any additional argument otherwise.

I got it working with this version

#!/bin/bash
alias php="[ -f path/to/hostip ] && php -dxdebug.remote_host=\"$( < path/to/hostip )\" || php

Two issues

1. it's too long (luxury problem)
2. when calling php path/to/any/script my further arguments aren't passed to the php call

I tried a function, which solves issue #2

#!/bin/bash
function phpx {
    if [ -f path/to/hostip ]; then
        php -dxdebug.remote_host="$( < path/to/hostip )" "$@"
    else
        php "$@"
    fi
}

But I still have issues

1. it's much more longer (luxury problem)
2. I can't use php as the alias for the function name

What I'm looking for is an alias for php like

alias php='php ( condition | true > pass file content as argument | false > pass nothing )'

And I want to be able to pass my further arguments to the alias.

Answer 1

help command:

command: command [-pVv] command [arg ...]
    Execute a simple command or display information about commands.

So, run command php "$@" inside the function to not have it call the function again. Or /usr/bin/php, but then you need to know the correct path.

You could still use the [ condition ] && php args.. || php other args trick within the function, but note that it will run the latter php command also if the first php command fails, so the if .. then .. else is more correct. Of course you could write that as a one-liner too, but assuming you're saving the function to your .bashrc or such, the length shouldn't matter much .

Answer 2

(This is really a comment, but needs formatting. Made it community wiki)

Note that (1)

A && B || C

is fundamentally different from (2)

if A; then B; else C; fi

in this situation: when A succeeds but B fails. When that happens, C will run in (1) but not in (2).

Answer 3

You could make your alias look like this:

alias php='_php_opts=(); [[ -f /path/to/hostip ]] && _php_opts+=( -dxdebug.remote_host="$( < path/to/hostip )" ); php "${_php_opts[@]}"`

but why would you when you could write something readable that does not pollute the global variable namespace.

php() {
    local _php_opts=()
    [[ -f /path/to/hostip ]] && _php_opts+=( -dxdebug.remote_host="$( < path/to/hostip )" )
    command php "${_php_opts[@]}" "$@"
}