Awk

The awk contains blocks

Skip headers and empty lines

awk 'NR > 1 && $2 != "" {print $2}' 

• Givinig new headers to the table
  (rename columns)

awk ' BEGIN{ printf "Sr No\tName\tSub\tMarsk\n"}

{print} file.txt' 

• If for some raeson u want to use awk itself use -f flag

• Varaibles

  • -v allows to pushc a varaible into the command

  awk -v name: Jerry 'BEGIN{printf "Name = %s\n", name}'
  

Patterns

• Searching for an pattern
  • it has to be in “/pattern/”
  • its important that this will output the entire row
• Counting Matches (in a loop)
  • Important to add END without it will print each iteration

• Counting letters

  • Awk has builtin function called lenght that returns the lenght of the string 1

  awk 'length($0) > 18' marks.tx
  

  - Ignore Case

awk 'BEGIN{IGNORECASE: 1} /amit/' marks.txt

Awk functions

awk 'BEGIN {
   a: 30;

   if (a==10)
   print "a: 10";
   else if (a == 20)
   print "a: 20";
   else if (a == 30)
   print "a: 30";
}'

Certainly! Below is a Markdown table summarizing the built-in string functions in AWK you mentioned, complete with brief descriptions and examples.

Function	Description	Example
asort(arr [, d [, how]])	Sorts the array arr and replaces the indexes with sequential integers starting at 1.	asort(arr); for (i in arr) { print arr[i]; }
asorti(arr [, d [, how]])	Sorts the array arr based on array indexes.	asorti(arr); for (i in arr) { print arr[i]; }
gsub(regex, sub, string)	Performs global substitution of regex with sub in string.	gsub("World", "Jerry", str);
index(str, sub)	Finds the position where sub starts in str. Returns 0 if not found.	index("One Two Three", "Two");
length(str)	Returns the length of str.	length("Hello, World !!!");
match(str, regex)	Returns the index of the first longest match of regex in str. Returns 0 if not found.	match("One Two Three", "Two");
split(str, arr, regex)	Splits str into an array arr based on regex.	split("One,Two,Three,Four", arr, ",");
printf(format, expr-list)	Returns a formatted string.	printf("sqrt(%f) = %f\n", 1024.0, sqrt(1024.0));
strtonum(str)	Returns the numeric value of str.	strtonum("123"); strtonum("0123"); strtonum("0x123");
sub(regex, sub, string)	Replaces the first occurrence of regex with sub in string.	sub("World", "Jerry", "Hello, World");
substr(str, start, l)	Returns a substring of str starting at start of length l.	substr("Hello, World !!!", 1, 5);
tolower(str)	Converts all upper-case characters in str to lower-case.	tolower("HELLO, WORLD !!!");
toupper(str)	Converts all lower-case characters in str to upper-case.	toupper("hello, world !!!");

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grep