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+====== Find Longest Line in a File ======
+<code bash>
+awk ' { if ( length > x ) { x = length } }END{ print x }' file.txt
+</code>
+====== Perform Floating Point Calculations ======
+''awk'' can be used for complex calculations, for example:
+<code bash>
+awk 'BEGIN {printf "%.3f\n", sin(30 * atan2(0, -1)/180)}'
+</code>
+will calculate $\sin(30^\circ)=sin(30rad * \frac{\pi}{180})$ and return:
+<code>
+.500
+</code>
+Since ''awk'' does not have a constant for $\pi$, we use ''atan2(0, -1)'' instead.
+====== Delimiter-Style ======
+Suppose you have a file ''input'' containing data separated by delimiters such as:
+<code>
+variable = value
+</code>
+or:
+<code>
+variable = value
+</code>
+The following command can be used to obtain ''value'':
+<code bash>
+awk -F"[ \t]*[=][ \t]*" '{ print $2 }' input
+</code>
+====== Remove Duplicate Entries in File Without Sorting ======
+To remove all duplicates from ''file.txt'' without sorting, issue:
+<code bash>
+awk '!x[$0]++' file.txt
+</code>
+====== Merge Lines by Two in File ======
+Given a file with the contents:
+<code>
+Q: What is this?
+A: This is a FAQ!
+</code>
+and you would like to achieve:
+<code>
+Q: What is this? A: This is a FAQ!
+</code>
+then the following ''awk'' one liner:
+<code bash>
+awk 'NR%2{printf "%s ",$0;next;}1' yourFile
+</code>
+will merge all the lines in a file by two.
+====== Convert Key-Value Map to JSON ======
+Given an input such as:
+<code>
+a1 : "abc
+c2  : def
+e3 : "ghi "
+f5 :" a     b"
+</code>
+The following awk script:
+<code bash>
+awk -F: '
+    function trim(s) {
+        return gensub(/^[ \t"]*|[ \t"]*$/, "", "g", s)
+    }
+    BEGIN {
+        printf "{"
+    }
+    NR > 1 {
+        printf(", ")
+    }
+    {
+        printf("\"%s\":\"%s\"", trim($1), trim(substr($0, index($0,":") + 1)));
+    }
+    END {
+        print "}"
+    }
+'
+</code>
+will return the JSON object:
+<code>
+{"a1":"abc","c2":"def","e3":"ghi","f5":"a     b"}
+</code>
+where keys and values are trimmed for spaces and quotes from the start and end.
+[[iot/openhab2/templates/apc_ups|One example application]] would be creating a JSON object out of the status of an APC UPS:
+<code bash>
+apcaccess | awk -F: '
+    function trim(s) {
+        return gensub(/^[ \t"]*|[ \t"]*$/, "", "g", s)
+    }
+    BEGIN {
+        printf "{"
+    }
+    NR > 1 {
+        printf(", ")
+    }
+    {
+        printf("\"%s\":\"%s\"", trim($1), trim(substr($0, index($0,":") + 1)));
+    }
+    END {
+        print "}"
+    }
+'
+</code>