CODEWITHSUNDEEP
shell
JumpOffBox
JumpOffBox

Reputation: 783

Too many arguments with && operator in shell?

if [ $(ps -ef | grep date) ] && [ $(ps -ef | grep time) ]
then
     echo "success"
else
    exit 1
fi

is giving [: too many arguments error

What is going wrong?

From a comment:

There are two processes running and I want to check if these two processes are running if executing my automated tool. For that I need to check if those two processes are running, you are right when you say grep is included in arguments it always succeeds I want to check only if two processes are running leaving out grep part. Can I do some thing like checking $? == 0 but how would I do that for both processes?

Upvotes: 0

Views: 158

Answers (2)

Gilles Quénot
Gilles Quénot

Reputation: 185229

Better do this, it will be lighter than multiple subshells $( ) and pipes | (many fork()s in the background) :

if pidof &>/dev/null date && pidof &>/dev/null time; then
     echo "success"
else
    exit 1
fi

No need the test commands :

[           # POSIX test

or

[[          # bash enhanced test

or

test        # word test

we use boolean logic here.

Upvotes: 1

Jonathan Leffler
Jonathan Leffler

Reputation: 754090

The [ command expects rather limited list of values. The output of your ps -ef commands could be generating a lot of data, which won't look like [ value1 = value2 ] etc which is what [ expects.

You could try:

if [ "$(ps -ef | grep date)" ] && [ "$(ps -ef | grep time)" ]
then echo "success"
else exit 1
fi

This will report success if there is at least one command referencing date and at least one command referencing time (and since the grep commands includes that argument, it should always succeed), but that may not be what you're after. With a single argument, as enforced by the double quotes, the [ command checks whether the argument is an empty string or not (success if it is not).

What are you really trying to do?

Upvotes: 1

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