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I'd like to run several commands on the command line.

In a normal case this is simple:

#cd /home && ls && echo "OK"
root   web   support
OK

However when one of the commands ends itself on a & this doesn't seem to work:

#killall vsftpd && /usr/sbin/vsftpd & && echo "OK"
-sh: syntax error: unexpected "&&"
OK

I've tried without the single trailing & but this obviously halts the processing of the latter echo. Just for fun tried a triple & but this also returns an error.

So my question; how can I get 

killall vsftpd
/usr/sbin/vsftpd &
echo "OK"

executed on one single line?

EDP
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2 Answers2

14

First, if you want to run multiple commands in one line, separate them by a ;:

cmd1 ; cmd2 ; cmd3

The && is the logical and operator. If you issue

cmd1 && cmd2

cmd2 will only run if cmd1 succeeded. That's important to mention (also see below).

If you use the & to run a command in background simply append the next command without the ; delimiter:

cmd1 & cmd2

The & is not a logical operator in this case, it tells bash to run cmd1 in background.

In your case, the commandline needs syntactically look like this:

killall vsftpd && /usr/sbin/vsftpd & echo "OK"

However, I guess you really meant this:

killall vsftpd ; /usr/sbin/vsftpd & echo "OK"

because otherwise you would not be able to start the process if it is not already running, since killall would return a non zero return code.

Even having this the code is quite fragile. I suggest to use your operating systems facilities to start vsftp as a daemon. I mean facilities like the command start-stop-daemon.

hek2mgl
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  • Thanks for pointing out the difference between `&&` and `;`. Seems in most cases `;` is preferable above `&&`. – EDP Mar 17 '16 at 16:33
2

You can encapsulate commands (or sequences of commands) in parentheses, like so:

# killall vsftpd && (/usr/sbin/vsftpd &) && echo "OK"

However, this doesn't make much sense semantically as the && token means “run subsequent command if previous command successful” (i.e., return value of 0), and the single & puts the command preceding it into the background (continuing immediately with the next command), which always yields success.

In your case, there really isn't any way to determine the success of running the vsftpd command when it is backgrounded, unless the executable offers command-line arguments running the thing as a daemon so you needn't background it manually.

curio77
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