Shell Programming and Scripting

This is not the same, for the single bracket version; there should be single = signs and double quotes around the left variable and the negation operator should work on the entire logical comparison, so one would need to use grouping to accomplish this:

Code:

if ! ( [ "$1" = "foo" ] || [ "$1" = "bar" ] )
then

The use of parentheses means using a subshell, so I think it is more efficient to use block grouping:

Code:

if ! { [ "$1" = "foo" ] || [ "$1" = "bar" ] ;}
then

Or use the logical equivalent:

Code:

if [ "$1" != "foo" ] && [ "$1" != "bar" ]
then

The equivalent using the features of test that are obsoleted in the POSIX specification would be:

Code:

if [ ! \( "$1" = "foo" -o "$1" = "bar" \) ]
then

-or-

Code:

if ! [ "$1" = "foo" -o "$1" = "bar" ]
then

---------- Post updated at 11:42 ---------- Previous update was at 09:24 ----------

Code:

if ! { [ "$var" = a ] || [ "$var" = b ] || [ "$var" = b ] ;}
then

If you are writing a Korn shell script and do not need POSIX compliancy you can use this:

Code:

if ! [[ $var == a || $var == b || $var == c ]]
then

To answer post #1 :
The correct syntax in your context is:

Code:

if [ 1 -eq 1 -a \( 2 -eq 2 -o 2 -eq 3 \) ]
then
  echo "true"
else
  echo "false"
fi

Note that the parentheses are escaped because we want to give them to "test" and not start a subshell.

@Scrutinizer
The word is "depreciated" not "deprecated" !
Anyway there is no way that the "-a" and "-o" syntax or the brackets will be "depreciated" no matter how often the Posix police mention it.

@methyl: Deprecation

Oops. I stand corrected. Word must have crept in from America. No such meaning in a UK English dictionary.

will post my question in new thread