is is possible to use two conditions in one line shell scripting

is is possible to use two conditions in one line shell scripting

like this
if [ "$foo" = bar && "$foo" = bar ];

i tried this example but didn't work

userx@MinTy:~
$ foo1=boo
$ foo2=bear

[ "$foo1" = "boo" ] && [ "$foo2" = "bear" ] && echo "say what?"

try that.
plus it is malformed

if [ "$foo" = bar && "$foo" = bar ];

two foo's same named variables. they can only hold one value so it will always come up false.
and
using 'if'

 if [ "$foo1" = "boo"  &&  "$foo1" = "bear" ]; then  echo "true"; else echo "false"; fi
bash: [: missing `]'
false

here

$ if [ "$foo1" = "boo" ] && [ "$foo1" = "bear" ]; then 
> echo "true"
> else
> echo "false"
> fi
false

and

 if [ "$foo1" = "boo" ]  &&  [ "$foo2" = "bear" ]; then  echo "true"; else echo "false"; fi
true

notice the naming of the vars.

It's 'man test' that explains the usage of 'test'. ('[' is an alias for 'test'.)

Edit: example:

if [ "$A" = 'a' -a "$B" = 'b' ]; then echo Both equal; fi

or

help test

since test is usually a shell builtin (and will take precedence over the coreutils binary).
also try

help [

and

help [[

Originally Posted by shlomo.hovir if [ "$foo" = bar && "$foo" = bar ]; i tried this example but didn't work

It works with bash improvement [[:

if [[ "${var1}" == "foo" && "${var2}" == "bar" ]];

So you have at least 4 possibilities:

• if [[ cond1 && cond2 ]];: see above
• if [ cond1 -a cond2 ];: see NevemTeve's post
• if [ cond1 ] && [ cond2 ];: see BW-userx's post (works as well with [[)
• [ cond1 ] && [ cond2 ] && ...: see BW-userx's post (works as well with [[)

and there is an additional trick which will work in some cases, so

# instead of
if [ "$var1" = bar && "$var2" = foo ];
# you can write:
if [ "${var1}${var2}" = barfoo ];

using -a -o && (or similar) may not do what you wish inside [ ], but works properly outside.
using [[ ]] is preferred (instead of [ ]

Originally Posted by NevemTeve '[' is an alias for 'test'.

No, unfortunately it is not really true. There is a binary /usr/bin/test, there is another /user/bin/[ which are not the same (different apps) - although yes, [theoretically?] they should work exactly the same way, but I'm not really sure about that (if they really identical). And additionally there is a bash built-in [ which may differ.

Originally Posted by pan64 No, unfortunately it is not really true. There is a binary /usr/bin/test, there is another /user/bin/[ which are not the same (different apps) - although yes, [theoretically?] they should work exactly the same way, but I'm not really sure about that (if they really identical). And additionally there is a bash built-in [ which may differ.

The GNU coreutils versions of [ and test do work the same way, with the exception that test doesn't handle common options like --version and --help: https://www.gnu.org/software/coreuti...nvocation.html

Bash's [ built-in is a synonym for its test built-in.

~$ help [
[: [ arg... ]
    Evaluate conditional expression.
    
    This is a synonym for the "test" builtin, but the last argument must
    be a literal `]', to match the opening `['.
~$ help test
test: test [expr]
    Evaluate conditional expression.
    
    Exits with a status of 0 (true) or 1 (false) depending on
    the evaluation of EXPR. [...]

Originally Posted by pan64 and there is an additional trick which will work in some cases, so # instead of if [ "$var1" = bar && "$var2" = foo ]; # you can write: if [ "${var1}${var2}" = barfoo ];

Yes it works in some cases indeed, but it's less accurate, see below

var1=bar
var2=foo
if [ "${var1}${var2}" = "barfoo" ]; then echo "same"; else echo "different"; fi

-> returns "same"

var1=barf
var2=oo
if [ "${var1}${var2}" = "barfoo" ]; then echo "same"; else echo "different"; fi

-> returns "same" as well...

That's why, if you really want to merge conditions, I would prefer something like the following:

var1=bar
var2=foo
if [ "${var1}${IFS}${var2}" = "bar${IFS}foo" ];

That last example is to me just getting to damn fancy for the "normal" reader. Where

if [[ "$foo" = "bar" ]] && [[ "$bar = "foo" ]] ; then ...

is to me more understandable to the lay person BASHing. namely me, and perhaps a few others..

Originally Posted by pan64 No, unfortunately it is not really true. There is a binary /usr/bin/test, there is another /user/bin/[ which are not the same (different apps) - although yes, [theoretically?] they should work exactly the same way, but I'm not really sure about that (if they really identical). And additionally there is a bash built-in [ which may differ.

In Linux they are separate binaries that are 99% identical.
Traditionally in Unix /usr/bin/[ and /usr/bin/test are linked.

No links here

userx@voided.org:~
$ ls -la /usr/bin/[
-rwxr-xr-x 1 root root 51448 Jul 11 19:42 '/usr/bin/['
userx@voided.org:~
$ ls -la /usr/bin/test
-rwxr-xr-x 1 root root 47360 Jul 11 19:42 /usr/bin/test

As per pan64

using [[ ]] is preferred

which I always(!) use, ref http://tldp.org/LDP/abs/html/testcon...ml#DBLBRACKETS and also when I was on the Korn shell course @ HP