How to get the Bash version number

There’s also a special array (BASH_VERSINFO) containing each version number in separate elements.

if ((BASH_VERSINFO[0] < 3))
then
  echo "Sorry, you need at least bash-3.0 to run this script."
  exit 1
fi

See 9.1. Internal Variables for more information:

# Bash version information:

for n in 0 1 2 3 4 5
do
  echo "BASH_VERSINFO[$n] = ${BASH_VERSINFO[$n]}"
done

# BASH_VERSINFO[0] = 3                      # Major version no.
# BASH_VERSINFO[1] = 00                     # Minor version no.
# BASH_VERSINFO[2] = 14                     # Patch level.
# BASH_VERSINFO[3] = 1                      # Build version.
# BASH_VERSINFO[4] = release                # Release status.
# BASH_VERSINFO[5] = i386-redhat-linux-gnu  # Architecture
                                            # (same as $MACHTYPE).