conditions

if/then

then and fi statements are required, the space around the [ and ] symbols are also required:

if [ condition ]; then statements(s); fi
 ---------------
cat ifthen
if [ 2 -eq 2 ]; then
echo "ok"
else echo "not ok";
fi

$ bash ifthen
ok
 ------------------
$ if [ 2 -eq 2 ]; then echo "ok" else echo "not ok"; fi
ok else echo not ok
------------------
-r return true onlly if file exists and is readable

cat ift2
if [ ! -r "$1" ]; then
echo "error reading file"
else echo "ok"
fi



$ bash ift2 ifthen
ok

$ bash ift2 ifthen3
error reading file