using a for loop to determine days of the week



#!/bin/bash
#   determine day of week the 15th is for July for various years
echo "the day of week the 15th occurs for July for these years"
echo "========================================================="
YEARS="1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970"
for x in $YEARS 
        do
        echo "Su Mo Tu We Th Fr Sa - $x"
        cal 7 $x | grep 15
        done
echo "========================================================="

the day of week the 15th occurs for July for these years:
=========================================================
Su Mo Tu We Th Fr Sa - 1960
10 11 12 13 14 15 16
Su Mo Tu We Th Fr Sa - 1961
 9 10 11 12 13 14 15
Su Mo Tu We Th Fr Sa - 1962
15 16 17 18 19 20 21
Su Mo Tu We Th Fr Sa - 1963
14 15 16 17 18 19 20
Su Mo Tu We Th Fr Sa - 1964
12 13 14 15 16 17 18
Su Mo Tu We Th Fr Sa - 1965
11 12 13 14 15 16 17
Su Mo Tu We Th Fr Sa - 1966
10 11 12 13 14 15 16
Su Mo Tu We Th Fr Sa - 1967
 9 10 11 12 13 14 15
Su Mo Tu We Th Fr Sa - 1968
14 15 16 17 18 19 20
Su Mo Tu We Th Fr Sa - 1969
13 14 15 16 17 18 19
Su Mo Tu We Th Fr Sa - 1970
12 13 14 15 16 17 18
=========================================================


if the output is sent to a file first, then edited to highlight 15, this would make it easier to see.
But we might be able to identify the day of the week some other way...

but to highlight 15, a simple command could be inserted in the script above:
     perl -pi -e 's$15$15$g' 


#!/bin/bash
#   determine day of week the 15th is for July for various years
LOG="day-of-the-week-15th-July.txt"
echo "the day of week the 15th occurs for July for these years" > $LOG
echo "=========================================================" >> $LOG
YEARS="1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970"
for x in $YEARS 
        do
        echo "Su Mo Tu We Th Fr Sa - $x"     >> $LOG 
        cal 7 $x | grep 15                   >> $LOG
        done
echo "=========================================================" >> $LOG
     perl -pi -e 's$15$15$g' $LOG
     cat $LOG

--> sh ./loop-date-15-July.txt
the day of week the 15th occurs for July for these years
=========================================================
Su Mo Tu We Th Fr Sa - 1960
10 11 12 13 14 15 16
Su Mo Tu We Th Fr Sa - 1961
 9 10 11 12 13 14 15
Su Mo Tu We Th Fr Sa - 1962
15 16 17 18 19 20 21
Su Mo Tu We Th Fr Sa - 1963
14 15 16 17 18 19 20
Su Mo Tu We Th Fr Sa - 1964
12 13 14 15 16 17 18
Su Mo Tu We Th Fr Sa - 1965
11 12 13 14 15 16 17
Su Mo Tu We Th Fr Sa - 1966
10 11 12 13 14 15 16
Su Mo Tu We Th Fr Sa - 1967
 9 10 11 12 13 14 15
Su Mo Tu We Th Fr Sa - 1968
14 15 16 17 18 19 20
Su Mo Tu We Th Fr Sa - 1969
13 14 15 16 17 18 19
Su Mo Tu We Th Fr Sa - 1970
12 13 14 15 16 17 18
=========================================================