CODEWITHSUNDEEP
bashmacosshellunixbsd
Lee Wise
Lee Wise

Reputation: 900

Format date variable in shell script

I'm trying to the month number of the last Monday of this week. I got it to check what day of the week it is and if it's not Monday then subtract x days and set that new date as the variable value.

What I'm having trouble with is formatting this variable to only get the month. Everything works except the 2nd to last line below.

startDate=$(date)
weekDayNum=$(date +'%u') # 1 is Monday

# If today is NOT Monday
if [ weekDayNum > 1 ];
then
    # Get the date for the last Monday
    newWeekDayNum=$(($weekDayNum-1))

    startDate=$(date -j -v-${newWeekDayNum}d)
fi

month=$(date -d "$startDate" +'%m')
echo $month```

Upvotes: 1

Views: 7029

Answers (2)

Jürgen Hötzel
Jürgen Hötzel

Reputation: 19717

[ weekDayNum > 1 ] doesn't test for numeric order. Use [ $weekDayNum -gt 10 ] (you also did not access the value of your weekDayNum variable).

It seems you have to supply the format string in the BSD variant of date:

This works for me:

#!/usr/bin/env bash                                                                                                                                                                                                

LANG=C                                                                                                                                                                                                             
startDate=$(date)                                                                                                                                                                                                  
weekDayNum=$(date +'%u') # 1 is Monday                                                                                                                                                                             

# If today is NOT Monday                                                                                                                                                                                           
if [ $weekDayNum -gt 1 ];                                                                                                                                                                                          
then                                                                                                                                                                                                               
    startDate=$(date -j -v "-$(($weekDayNum - 1))d")                                                                                                                                                               
fi                                                                                                                                                                                                                 

month=$(date -j  -f "%a %b %d %T %Z %Y"  "${startDate}" +'%m')                                                                                                                                                     
echo $month

Upvotes: 1

Kaushik Nayak
Kaushik Nayak

Reputation: 31648

Use expr to convert it to number.

month=$(date -d "$startDate" +'%m')
month=$(expr $month + 0)
echo $month

Output:

8

Upvotes: 0

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