From f98efee4918905ea4603a53f09caedae5394c583 Mon Sep 17 00:00:00 2001
From: Andrew Stowell <andrew@digitaladapt.com>
Date: Wed, 27 Sep 2023 15:16:00 -0400
Subject: [PATCH] more robust public ip look up.

---
 4-public-ip.sh | 44 ++++++++++++++++++++++++++++++++++++++++----
 6-public-ip.sh | 43 +++++++++++++++++++++++++++++++++++++++++--
 all-crons.sh   | 32 ++++++++++++++++----------------
 3 files changed, 97 insertions(+), 22 deletions(-)

diff --git a/4-public-ip.sh b/4-public-ip.sh
index 1538e1e..fe13280 100755
--- a/4-public-ip.sh
+++ b/4-public-ip.sh
@@ -1,8 +1,44 @@
 #!/bin/bash
 
-# works consistently if you specify the -4 to force IPv4
-dig -4 +short A myip.opendns.com @resolver1.opendns.com
+# there are a few different ways to resolve public-ip,
+# keep trying until we get a result
 
-#curl --fail --silent --show-error https://ipinfo.io/ip
-#echo ""
+# dig
+if [[ -n $(command -v "dig") ]]; then
+    # via opendns
+    address=$(dig "@resolver1.opendns.com" -4 "myip.opendns.com" "A" "+short")
+    if [[ "$?" -ne "0" ]]; then
+        # dig was unsuccessful
+        echo "$address" 1>&2
+        address=""
+    fi
+fi
+
+# curl
+if [[ -z "$address" ]] && [[ -n $(command -v "curl") ]]; then
+    # via ipinfo.io
+    address=$(curl -4 --fail --silent --show-error "https://ipinfo.io/ip")
+
+    if [[ -z "$address" ]]; then
+        # via google
+        address=$(curl -4 --fail --silent --show-error "https://domains.google.com/checkip")
+    fi
+fi
+
+# wget
+if [[ -z "$address" ]] && [[ -n $(command -v "wget") ]]; then
+    # via ipinfo.io
+    address=$(wget -4 --quiet --output-document - "https://ipinfo.io/ip")
+
+    if [[ -z "$address" ]]; then
+        # via google
+        address=$(wget -4 --quiet --output-document - "https://domains.google.com/checkip")
+    fi
+fi
+
+if [[ -n "$address" ]]; then
+    echo "$address"
+else
+    echo 'Tried everything, unable to resolve IP address.' 1>&2
+fi
 
diff --git a/6-public-ip.sh b/6-public-ip.sh
index 9bd7b32..84070ed 100755
--- a/6-public-ip.sh
+++ b/6-public-ip.sh
@@ -1,5 +1,44 @@
 #!/bin/bash
 
-# works consistently if you specify the -6 to force IPv6
-dig -6 +short AAAA myip.opendns.com @resolver1.opendns.com
+# there are a few different ways to resolve public-ip,
+# keep trying until we get a result
+
+# dig
+if [[ -n $(command -v "dig") ]]; then
+    # via opendns
+    address=$(dig "@resolver1.opendns.com" -6 "myip.opendns.com" "AAAA" "+short")
+    if [[ "$?" -ne "0" ]]; then
+        # dig was unsuccessful
+        echo "$address" 1>&2
+        address=""
+    fi
+fi
+
+# curl
+if [[ -z "$address" ]] && [[ -n $(command -v "curl") ]]; then
+    # via ipinfo.io
+    address=$(curl -6 --fail --silent --show-error "https://v6.ipinfo.io/ip")
+
+    if [[ -z "$address" ]]; then
+        # via google
+        address=$(curl -6 --fail --silent --show-error "https://domains.google.com/checkip")
+    fi
+fi
+
+# wget
+if [[ -z "$address" ]] && [[ -n $(command -v "wget") ]]; then
+    # via ipinfo.io
+    address=$(wget -6 --quiet --output-document - "https://v6.ipinfo.io/ip")
+
+    if [[ -z "$address" ]]; then
+        # via google
+        address=$(wget -6 --quiet --output-document - "https://domains.google.com/checkip")
+    fi
+fi
+
+if [[ -n "$address" ]]; then
+    echo "$address"
+else
+    echo 'Tried everything, unable to resolve IP address.' 1>&2
+fi
 
diff --git a/all-crons.sh b/all-crons.sh
index 2600d3d..a8aff02 100755
--- a/all-crons.sh
+++ b/all-crons.sh
@@ -1,24 +1,24 @@
 #!/bin/bash
 
-# this only works if your crontab uses three spaces for each section,
-# like the following spacing example:
-#m  h   dom mon dow command
+# quickly generate a script file which will contain all crontab tasks.
+# optionally takes filename to use, defaults to 'crontasks.sh'.
+crontasks="$1"
 
-# quickly generate a script file which will run each crontab task
-# optionally takes filename to use, otherwise defaults 'crontasks.sh'
-FILENAME="$1"
-
-if [ -z "$FILENAME" ]; then
-    FILENAME='crontasks.sh'
+if [[ -z "$crontasks" ]]; then
+    crontasks='crontasks.sh'
 fi
 
-echo "#!/bin/bash" > "$FILENAME"
-echo "" >> "$FILENAME"
+# prefix file we are generating
+echo "#!/bin/bash" > "$crontasks"
+echo "" >> "$crontasks"
 
-# list crontab, remove comments and empty lines,
-# expect cron time formatting to be the first 20 characters,
-# so drop the 21st character onward to standard out.
-crontab -l | grep -Ev '^(#|$)' | cut -c 21- >> "$FILENAME"
+# list crontab, remove comments, convert tabs to space, squeeze the spaces,
+# then take the sixth field "command" and add it to the file.
+# could have issues if a task has a "#" in the middle.
+crontab -l | grep -o '^[^#]*' | tr "\t" ' ' | tr -s ' ' | cut -s -d ' ' -f 6- >> "$crontasks"
 
-chmod +x "$FILENAME"
+echo "" >> "$crontasks"
+
+# make the file executable, so we are good to go
+chmod +x "$crontasks"