What is /usr/bin/[?

linux shell command test

116

Solution 1

It's an alternative form of the 'test' command. Mostly used in scripts.

i.e.

if [ $VAR ]
then
    echo $VAR exists!
fi

Solution 2

It's what you call when you are using something like

if [ -e foo ]; then ...

in a shell script (but most shells have it as a buildin this days). man test should give you the docs.

Solution 3

As others pointed out, [ is the shell's condition evaluation utility - test.

In fact, there is a manual page for that!

$ man [

should give you more details about the opening square bracket.

Btw, in OS X, [ is located in /bin/[ :)

116

user1652922

Updated on September 17, 2022

Comments

user1652922 almost 2 years

I have a list view populate with numbers, and a edit text that sum the amount of numbers in the list view, I have written a implementation of ontouch, to delete rows in the list view, my question is: is there a way to delete the value that I delete in the list view on the edit text. for example if I delete the row 7 of 10 rows and its has a value of 5, and the amount is 35 display on the edit text, now the edit text must have 30.

thank you I will appreciate it

here some codes:

 private void showListViewData() {

    String z = "";
    String zQN = "Nu";
    String zPL = "Pl";  
    String zTR = "Tr";

    int x = Integer.parseInt(inJugada.getText().toString());
    int y = Integer.parseInt(inValor.getText().toString());

    String s = Integer.toString(x); 

    inJugada.setText(s);

    inValor.setText(String.valueOf(y));

   if(s.length() == 2){
       z = zQN;

   }else if(s.length() == 4){

       z = zPL;

   }else if(s.length() == 6){
       z = zTR;
   }

    for(int i=0; i<mData.size(); i++)
        mData.get(i);

    mData.add(new Data(z, x, y));
    Collections.sort(mData);
    Collections.synchronizedCollection(mData);

    // add new data to list and refresh
    mAdapter.notifyDataSetChanged();

Florian Diesch about 14 years

But unlike test it requires the last arg to be a ]
Josh about 14 years

Thanks. That's what I figured but I was surprised because I thought [ was a bash builtin
Josh about 14 years

I would accept your answer but Zypher beat you to it by a few seconds... sorry :-)
Mo. about 14 years

[ is a bash builtin, but so is test. not all shells are created equal — in plenty of them, test (and [) aren’t builtins.
Matt Simmons about 14 years

There is a bash built-in, or at least, my system is acting as though there is. [ --help gives different input than /usr/bin/[ --help
Zoredache about 14 years

test and [ are builtin to bash, but not necessarily all other shells. You could temporarily move out of the path and run a bash script that uses either and you will see that the script still works.
Dennis Williamson about 14 years

Or try type -a [ which will show that [ is a Bash builtin and /usr/bin/[. The order shown is the order of preference.
Josh about 14 years

This must be the most upvoted string of comments ever, lol.
user1686 about 14 years

[ $VAR ] fails when $VAR is empty or not set. Use [ "$VAR" ] instead.