feat: add --static-ipv4 option, auto parse current network settings. (#131)

* feat: use static ip without manually typing it

* fix(cidr_to_netmask): rewrite to support sh

* refactor: remove cidr_to_netmask(), set cidr directly

https://lists.debian.org/debian-boot/2012/09/msg00239.html

* refactor: rename option --static-ip to --static-ipv4

* Add --static-ipv4 doc

---------

Co-authored-by: Anonymous <>
Co-authored-by: Brent, Yang Bohan <youthdna@live.com>

README.md

@@ -71,6 +71,7 @@ Otherwise, you can run this command to revert all changes made by the script:
  * `--interface <string>` Manually select a network interface, e.g. eth1
  * `--ethx` Disable *Consistent Network Device Naming* to get interface names like *ethX* back
  * `--ip <string>` Disable the auto network config (DHCP) and configure a static IP address, e.g. `10.0.0.2`, `1.2.3.4/24`, `2001:2345:6789:abcd::ef/48`
+ * `--static-ipv4` Disable the auto network config (DHCP) and configure with the current IPv4 address and gateway detected automatically
  * `--netmask <string>` e.g. `255.255.255.0`, `ffff:ffff:ffff:ffff::`
  * `--gateway <string>` e.g. `10.0.0.1`, `none` if no gateway
  * `--dns '8.8.8.8 8.8.4.4'`

debi.sh

@@ -274,6 +274,14 @@ while [ $# -gt 0 ]; do
             mirror_host=mirrors.tuna.tsinghua.edu.cn
             ntp=time.amazonaws.cn
             ;;
+        --static-ipv4)
+            ip=$(ip r get 1.1.1.1 | awk '/src/ {print $7}')
+            gateway=$(ip r get 1.1.1.1 | awk '/via/ {print $3}')
+            _cidr=$(ip -o -f inet addr show | grep -w "$ip" | awk '{print $4}' | cut -d'/' -f2)
+            ip="$ip/$_cidr"
+            hostname=$(hostname)
+            interface=$(ip r get 1.1.1.1 | awk '/dev/ {print $5}')
+            ;;
         --interface)
             interface=$2
             shift