Multiple Commands in Single Line

[cawill]

I know ; and && can be used to put multiple commands into a single line, but they don't always work.

How do you have a single line command were it runs to programs at the same time even if the other one runs or fails to run.

For example:
conky ; avant-window-navigator or the && variant will only run the command that is first (either conky or AWN depending on which is first)

Also when replacing window managers (eg metacity --replace) the commands stop there and don't continue.

How can I get round this?

[Bachstelze]

command &

Will run the command in the background and bring you back to the prompt, so you can do


command1 &
command2 &
command3 &

and so on...

[ynnhoj]

something like

$ command1 & ; command2 &
ought to work too, if you really want it to be a one-liner.

[garba]

try this:

(command1 &);(command2 &)

that should spawn two concurrent processes

[init1]

something like

$ command1 & ; command2 &
ought to work too, if you really want it to be a one-liner.
No.


ls & ; ls &
bash: syntax error near unexpected token `;'

[Bachstelze]

Use parentheses, as garba suggested.

[Compucore]

I've always used the pipe character which is | for putting multiple commands on the same line. It worked for me in linux before. And when I used to type commands in AIX when I was in the command line. Give that a try as well as an alternative. :D

Compucore

[ynnhoj]

No.


ls & ; ls &
bash: syntax error near unexpected token `;'

i did

leafpad & ; mirage & ; gtkpod &
and it was a-okay. but my shell is zsh, not bash -- perhaps that explains it?

edit: and fer the record, the example you posted works fine for me as well :)

[ynnhoj]

I've always used the pipe character which is | for putting multiple commands on the same line. It worked for me in linux before. And when I used to type commands in AIX when I was in the command line. Give that a try as well as an alternative. :D

Compucore
pipe is a bit of a different story, though -- it will redirect the output of one program into another. for example, to read the listing of a directory with many files, page-by-page, you could do

ls | more
which, of course, is considerably different from

ls & ; more &
(or something along those lines)

[gaellafond]

Using this:
command1; command2

Will execute both commands, whatever append after the first one.

If you want to execute 1 command, than execute a second one only if the first one succeed, you have to use this:
command1 && command2

Explanation:
The && is the binary AND operator. When you use it with commands, the line is evaluate as a Boolean expression. To be TRUE (succeed), the expression must have both parts TRUE. If the first one is FALSE (the command fail), the system do not need to evaluate the second one since "FALSE && whatever" is always FALSE.

NOTE: You can use this with multiple commands:
command1 && command2 && command3 && command4
You can also mix it with the OR operator (two pipes ||), but it make code very difficult to understand. If you want to execute something more complex, use the if statement.

[janpetel]

I use this sometimes to start some apps full screen. E.g. ('Loopy' is a game I sometimes play from the Simon Tatham collection and is only an example. I have other apps that require more wmctrl tweaking, like displaying vlc nicely on a second monitor):

# (loopy &) ; (sleep 1) ; (wmctrl -F -r Loopy -b add,fullscreen &)

[omit the hash tag!]

In this case, I obviously want the sleep command to execute first (to ensure the game is visible), so it has no ampersand there.
This has to go in a script file to be called from a desktop launcher, still, because in a launcher this doesn't work. If someone could tell me why?

And if you have a script file, why bother with single lines?

[Iowan]

Closed.

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