In /usr/bin/kernel-install line 62:
    if [ "$i" == "--help" -o "$i" == "-h" ]; then
                          ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/kernel-install line 69:
if [ "$1" == "--verbose" -o "$1" == "-v" ]; then
                         ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/kernel-install line 89:
    read MACHINE_ID < /etc/machine-id
    ^--^ SC2162: read without -r will mangle backslashes.


In /usr/bin/kernel-install line 99:
    trap "rm -rf '$ENTRY_DIR_ABS'" EXIT INT QUIT PIPE
                  ^------------^ SC2064: Use single quotes, otherwise this expands now rather than when signalled.


In /usr/bin/kernel-install line 139:
                    echo "+$f add $KERNEL_VERSION $ENTRY_DIR_ABS $KERNEL_IMAGE ${INITRD_OPTIONS[@]}"
                                                                               ^------------------^ SC2145: Argument mixes string and array. Use * or separate argument.


In /usr/bin/kernel-install line 142:
                if [[ $x == $SKIP_REMAINING ]]; then
                            ^-------------^ SC2053: Quote the right-hand side of == in [[ ]] to prevent glob matching.


In /usr/bin/kernel-install line 146:
                ((ret+=$x))
                       ^-- SC2004: $/${} is unnecessary on arithmetic variables.


In /usr/bin/kernel-install line 166:
                if [[ $x == $SKIP_REMAINING ]]; then
                            ^-------------^ SC2053: Quote the right-hand side of == in [[ ]] to prevent glob matching.


In /usr/bin/kernel-install line 170:
                ((ret+=$x))
                       ^-- SC2004: $/${} is unnecessary on arithmetic variables.


In /usr/bin/kernel-install line 187:
exit $ret
     ^--^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
exit "$ret"

For more information:
  https://www.shellcheck.net/wiki/SC2145 -- Argument mixes string and array. ...
  https://www.shellcheck.net/wiki/SC2053 -- Quote the right-hand side of == i...
  https://www.shellcheck.net/wiki/SC2064 -- Use single quotes, otherwise this...