Video
Notes
- Basic syntax:
mynum=200
if [ $mynum -eq 200 ]
then
echo "The condition is true."
else
echo "The condition is false."
fi
- Checks within single brackets
- Between variables/literals
- Comparing integers
-eq (equal to)-ne (not equal to)-gt (greater than)-ge (greater than or equal)-lt (less than)-le (less than or equal)
- Comparing strings
= (equal to)!= (not equal to)
- Comparing files
-nt (newer than)-ot (older than)
- Before the variable/literal
-f (regular file exists)-d (directory exists)-n (string has non-zero length)-z (string has length zero)
- Combining checks
- Checks without brackets
command -v COMMAND (command exists)COMMAND (command exits with return code 0)
! reverses the following condition