From: Bill Thompson (bill.thompson@GOODYEAR.COM)
Date: Fri Jul 19 2002 - 09:38:42 EDT
This is a Borne/Korn shell question which is not AIX specific. Sorry if
it's somewhat off topic.
I was reviewing an old script and found the following conditional:
if [ -a $filename ]; then ...
My immediate reaction is that the -a should have been a -f
While the -f is probably the more appropriate test, I did some
experimenting at the command line...
if [ -a ]; then echo true; else echo false; fi
true
if [ -a .profile ]; then echo true; else echo false; fi
true
if [ -a not_a_file ]; then echo true; else echo false; fi
false
-a is the binary AND which is typically used between two conditionals like
this:
if [ $A -lt $B -a $C = "OK" ]; then ...
Assuming the contents of "$filename" is the name of a file (or directory),
can somebody explain why "if [ -a $filename ]" returns TRUE if the file
exists and FALSE if the file does not exist?
BTW:
if [ .profile ] or if [ not_a_file ] both return TRUE (which is what I
would expect because the strings are not null).
TIA
Bill Thompson
The Goodyear Tire & Rubber Company
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