I'm not sure where to ask this question, but here it goes.
I was looking in /usr/bin ans see a file named:
[EMAIL PROTECTED]:/usr/bin$ ls -la [
-rwxr-xr-x 2 root root 20092 Jun 2 17:05 [
[EMAIL PROTECTED]:/usr/bin$ ldd [
libc.so.6 => /lib/libc.so.6 (0x40020000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
[EMAIL PROTECTED]:/usr/bin$ ./[ --help
Usage: ./[ EXPRESSION
or: [ EXPRESSION ]
or: ./[ OPTION
Exit with the status determined by EXPRESSION.
--help display this help and exit
--version output version information and exit
EXPRESSION is true or false and sets exit status. It is one of:
( EXPRESSION ) EXPRESSION is true
! EXPRESSION EXPRESSION is false
EXPRESSION1 -a EXPRESSION2 both EXPRESSION1 and EXPRESSION2 are
true EXPRESSION1 -o EXPRESSION2 either EXPRESSION1 or EXPRESSION2 is true
[-n] STRING the length of STRING is nonzero
-z STRING the length of STRING is zero
STRING1 = STRING2 the strings are equal
STRING1 != STRING2 the strings are not equal
INTEGER1 -eq INTEGER2 INTEGER1 is equal to INTEGER2
INTEGER1 -ge INTEGER2 INTEGER1 is greater than or equal to INTEGER2
INTEGER1 -gt INTEGER2 INTEGER1 is greater than INTEGER2
[EMAIL PROTECTED]:/usr/bin$ ./[ --help
Usage: ./[ EXPRESSION
or: [ EXPRESSION ]
or: ./[ OPTION
Exit with the status determined by EXPRESSION.
--help display this help and exit
--version output version information and exit
EXPRESSION is true or false and sets exit status. It is one of:
( EXPRESSION ) EXPRESSION is true
! EXPRESSION EXPRESSION is false
EXPRESSION1 -a EXPRESSION2 both EXPRESSION1 and EXPRESSION2 are
true EXPRESSION1 -o EXPRESSION2 either EXPRESSION1 or EXPRESSION2 is true
[-n] STRING the length of STRING is nonzero
-z STRING the length of STRING is zero
STRING1 = STRING2 the strings are equal
STRING1 != STRING2 the strings are not equal
INTEGER1 -eq INTEGER2 INTEGER1 is equal to INTEGER2
INTEGER1 -ge INTEGER2 INTEGER1 is greater than or equal to INTEGER2
INTEGER1 -gt INTEGER2 INTEGER1 is greater than INTEGER2
INTEGER1 -le INTEGER2 INTEGER1 is less than or equal to INTEGER2
INTEGER1 -lt INTEGER2 INTEGER1 is less than INTEGER2
INTEGER1 -ne INTEGER2 INTEGER1 is not equal to INTEGER2
FILE1 -ef FILE2 FILE1 and FILE2 have the same device and inode numbers
FILE1 -nt FILE2 FILE1 is newer (modification date) than FILE2
FILE1 -ot FILE2 FILE1 is older than FILE2
-b FILE FILE exists and is block special
-c FILE FILE exists and is character special
-d FILE FILE exists and is a directory
-e FILE FILE exists
-f FILE FILE exists and is a regular file
-g FILE FILE exists and is set-group-ID
-h FILE FILE exists and is a symbolic link (same as -L)
-G FILE FILE exists and is owned by the effective group ID
-k FILE FILE exists and has its sticky bit set
-L FILE FILE exists and is a symbolic link (same as -h)
-O FILE FILE exists and is owned by the effective user ID
-p FILE FILE exists and is a named pipe
-r FILE FILE exists and is readable
-s FILE FILE exists and has a size greater than zero
-S FILE FILE exists and is a socket
-t [FD] file descriptor FD (stdout by default) is opened on a terminal
-u FILE FILE exists and its set-user-ID bit is set
-w FILE FILE exists and is writable
-x FILE FILE exists and is executable
Beware that parentheses need to be escaped (e.g., by backslashes) for
shells.
INTEGER may also be -l STRING, which evaluates to the length of STRING.
Report bugs to <bug-sh-utils@gnu.org>.
[EMAIL PROTECTED]:/usr/bin$
anybody know is this a valid file, and if so, what is it?