In /logs/firmware/unblob_extracted/firmware_extract/DIR-600_fw_revb5_214b01_ALL_de_20130122/dir600b_v2.14_d1mg.bin_extract/1179788-3612812.squashfs_v4_le_extract/etc/scripts/conntrack_flush.sh line 3:

echo [$0][start] > /dev/console

      ^-- SC2086 (info): Double quote to prevent globbing and word splitting.

         ^-----^ SC2102 (info): Ranges can only match single chars (mentioned due to duplicates).

Did you mean:

echo ["$0"][start] > /dev/console

In /logs/firmware/unblob_extracted/firmware_extract/DIR-600_fw_revb5_214b01_ALL_de_20130122/dir600b_v2.14_d1mg.bin_extract/1179788-3612812.squashfs_v4_le_extract/etc/scripts/conntrack_flush.sh line 5:

ICMP=`cat /proc/sys/net/ipv4/netfilter/ip_conntrack_icmp_timeout`

     ^-- SC2006 (style): Use $(...) notation instead of legacy backticks `...`.

Did you mean:

ICMP=$(cat /proc/sys/net/ipv4/netfilter/ip_conntrack_icmp_timeout)

In /logs/firmware/unblob_extracted/firmware_extract/DIR-600_fw_revb5_214b01_ALL_de_20130122/dir600b_v2.14_d1mg.bin_extract/1179788-3612812.squashfs_v4_le_extract/etc/scripts/conntrack_flush.sh line 8:

echo $ICMP > $PROC

     ^---^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:

echo "$ICMP" > $PROC

In /logs/firmware/unblob_extracted/firmware_extract/DIR-600_fw_revb5_214b01_ALL_de_20130122/dir600b_v2.14_d1mg.bin_extract/1179788-3612812.squashfs_v4_le_extract/etc/scripts/conntrack_flush.sh line 9:

echo [$0][finish] > /dev/console

      ^-- SC2086 (info): Double quote to prevent globbing and word splitting.

         ^------^ SC2102 (info): Ranges can only match single chars (mentioned due to duplicates).

Did you mean:

echo ["$0"][finish] > /dev/console

For more information:

  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...

  https://www.shellcheck.net/wiki/SC2102 -- Ranges can only match single char...

  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...

[*] Source file conntrack_flush.sh