Re: Strange /usr/bin file
On Mon, Feb 11, 2008 at 10:22:21AM +0100, Mirco Piccin wrote:
> Hi all.
> I find in my Debian Lenny machine this file, in /usr/bin folder:
>
> -rwxr-xr-x 1 root root 34504 2008-01-29 04:03 [
>
> Who created this file? What does it do?
I presume you mean "what" created this file?
chrisb@box:~$ dpkg -S /usr/bin/[
dpkg: /usr/bin/[ not found.
Huh?
chrisb@box:~$ ls -al /usr/bin/[
-rwxr-xr-x 1 root root 24752 2007-01-31 07:51 /usr/bin/[
Ahhh OK ... ummm ... ahhh!!
chrisb@box:~$ help [
[: [ arg... ]
This is a synonym for the "test" builtin, but the last
argument must be a literal `]', to match the opening `['.
[[ ... ]]: [[ expression ]]
Returns a status of 0 or 1 depending on the evaluation of the conditional
expression EXPRESSION. Expressions are composed of the same primaries used
by the `test' builtin, and may be combined using the following operators
( EXPRESSION ) Returns the value of EXPRESSION
! EXPRESSION True if EXPRESSION is false; else false
EXPR1 && EXPR2 True if both EXPR1 and EXPR2 are true; else false
EXPR1 || EXPR2 True if either EXPR1 or EXPR2 is true; else false
When the `==' and `!=' operators are used, the string to the right of the
operator is used as a pattern and pattern matching is performed. The
&& and || operators do not evaluate EXPR2 if EXPR1 is sufficient to
determine the expression's value.
nice and clear :-(
chrisb@box:~$ man -k [
apropos: fatal: regex `[': Invalid regular expression
chrisb@box:~$ man -k "["
apropos: fatal: regex `[': Invalid regular expression
chrisb@box:~$ man -k \[
apropos: fatal: regex `[': Invalid regular expression
chrisb@box:~$ man -k "\["
[ (1) - check file types and compare values
I don't think the "bash builtin [" is the same as the "/usr/bin/["
chrisb@box:~$ man [
is the same as
chrisb@box:~$ man test
Any bash scripting guide/tutorial should explain its use in depth.
--
Chris.
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--
Chris.
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