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Can you just:
if cmp -s "$f" "$dir2/b"; then
echo "same"
else
echo "not same"
fi
?
If one doesn't exist, cmp will return 1 (false). If they both exist and are the same, then it will return 0 (true).
Kyle
On 2/19/06, Jeff Abrahamson <jeff@purple.com> wrote:
In a bash script I want to compare two files (one or both of which may
not exist) and take a certain action if they *both* exist and are
identical.
Refresher, cmp returns 0 on equality, 1 on inequality, 2 on error such
as one or both files doesn't exist.
The following attempt fails miserably (at the syntax level, for
obvious reasons):
if [ (cmp -s "$f" "$dir2/$b") -a $? == 0 ]; then
Anyone know how to combine a subshell invocation with a logical
operation in an if clause?
I'd like to be more elegant than a double if, merely on principle:
if [ -r "$f" -a -r "$dir2/$b" ]; then
if ( cmp -s ... ); then ...
--
Jeff
Jeff Abrahamson <http://www.purple.com/jeff/> +1 215/837-2287
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