If
if [ [ $1 ]]
then
echo Hello $1
else
echo Provide name
fi
and= or=
[ condition ] && var=value_when_true || var=value_when_false
For Loop
# from..upto..step
for i in {0..10..2}
do
echo "Welcome $i times"
done
Sub-String
# skip 3 + take 4
u="is WORD a"
echo "${u:3:4}"
more to be added…