[1]

awk 'BEGIN{
stock["orange"] = 100
stock["apple"] = 200
stock["grapes"] = 30
stock["pineapple"] = 10

for ( i in stock )
   if ( stock[i] > 50 ) printf "%-13s%3d\n", i, stock[i]
}' < /dev/null

[2]

#!/bin/sh
awk '{
fruit[$1] += $2
print "We have", fruit[$1], $1
}
END{
for (i in fruit) {
   print "Summary:"
   print i, fruit[i]
}
}'

[3]

The backslash at the end of each line is tcsh.
It is not needed if you put the script in a file.

#/bin/sh

# Script for extracting information from a table
# for COMP111 Lab session
#
# By Chan Kam Fai

awk '\
  BEGIN {  \
    FS = ":" \
#    Count["M"] = 0; \
#    Count["F"] = 0; \
  } \
 \
  { Name[NR] = $1; \
    ID[NR] = $2; \
#    printf "|%s|\n", $3 \
    Count[$3] += 1; \
    Dept[NR] = $4; \
    Year[NR] = $5; \
  } \
 \
  END { \
    for (i = 1; i <= 3; i++) { \
      printf "Year %d\n\n", i \
      printf "Name                  ID        Dept\n" ; \
      printf "--------------------  --------  ----\n" ; \
      for (j = 1; j <= NR; j++) \
        if (Year[j] == i) \
          printf "%-20s  %s  %s\n", Name[j], ID[j], Dept[j] \
      printf "\n========================================\n\n" \
    } \
    printf "Some Statistics:\n\n" ; \
    printf "Number of male students : %d\n", Count["M"] ; \
    printf "Number of female students : %d\n", Count["F"] ; \
  } '