awk

# execute awk file
awk -f users.awk /etc/passwd

# print specific column and show total lines processed
BEGIN { FS=":" ; print "Username"}
{print $1}
END {print "Total users= " NR}

# print column where it meets critera
BEGIN { FS=":" ; print "Username"}
$3>499 {print $1}

# count lines beginning with 'root' and print total users
BEGIN { FS=":" ; print "Username"}
/^root/ {print $1 ; count++}
END {print "Total users= " count}

# Uppercase 1st column, lowercase 2nd column in comma-separted file with substituting grouping
# compare to same sed command above. this is much easier
awk -F"," {print toupper($1), tolower($2), $3} file.csv

# extract xml records which are separated by two new lines
BEGIN { RS="\n\n"}
$0 ~ search {print}

awk -f xml.awk search=example xmlfile

# Count number of specific element
BEGIN { FS=" "; print "Log access"}
{ip[$1]++} // value $1 is the key (associative array)
END { for (i in ip)
print i, " has accesed ", ip[i], "times."
}

# print max number of specific element
BEGIN { FS=" "; print "Most popular browser"}
{browser[$1]++}
END { for (b in browser)
if (max < browser[b]) {
  max = browser[b];
  maxbrwoser = b;
}
print "Most access was from ", maxbrowser, " and ", max, " times."
}