How do you find the difference between two dates in shell?
How do you find the difference between two dates in shell?
In a shell environment/script you can get it with date ‘+%s’ At the time of writing, the current time is 1321358027 . To compare with 2011-11-04 (my birthday), date ‘+%s’ -d 2011-11-04 , yielding 1320361200 . Subtract: expr 1321358027 – 1320361200 gives 996827 seconds, which is expr 996827 / 86400 = 11 days ago.
How do I find the difference between two dates in unix?
- Provide valid time string in A and B.
- Use date -d to handle time strings.
- Use date %s to convert time strings to seconds since 1970 (unix epoche)
- Use bash parameter expansion to subtract seconds.
- divide by seconds per day (86400=60*60*24) to get difference as days.
- ! DST is not taken into account ! See this answer at unix.
How do I find the number of days between two dates in unix?
- datediff() {
- d1=$(date -d “$1” +%s)
- d2=$(date -d “$2” +%s)
- echo $(( (d1 – d2) / 86400 )) days.
- }
- $ datediff ‘1 Nov’ ‘1 Aug’
- 91 days.
How do you subtract dates in unix?
4 Answers. The easiest way is to convert the date to a unix time_t value (i.e. seconds since the beginning of the epoch, or ‘1-1-1970 00:00:00’), and then substract 30 days * 86400 seconds per day from that number.
How do I echo date in Shell?
Sample shell script to display the current date and time #!/bin/bash now=”$(date)” printf “Current date and time %s\n” “$now” now=”$(date +’%d/%m/%Y’)” printf “Current date in dd/mm/yyyy format %s\n” “$now” echo “Starting backup at $now, please wait…” # command to backup scripts goes here # …
What is let in bash?
On Unix-like operating systems, let is a builtin command of the Bash shell that evaluates arithmetic expressions. Description. Arithmetic operators. Exit status.
How do you display current day as full weekday in Unix?
From the date command man page:
- %a – Displays the locale’s abbreviated weekday name.
- %A – Displays the locale’s full weekday name.
- %b – Displays the locale’s abbreviated month name.
- %B – Displays the locale’s full month name.
- %c – Displays the locale’s appropriate date and time representation (default).
How do you do math in Bash?
The Bash shell has a large list of supported arithmetic operators to do math calculations….What are the Bash Arithmetic Operators?
| Arithmetic Operator | Description |
|---|---|
| !, ~ | logical and bitwise negation |
| ** | exponentiation |
| *, /, % | multiplication, division, remainder (modulo) |
| +, – | addition, subtraction |
How do you minus days from current date in Java?
The minusDays() method of LocalDate class in Java is used to subtract the number of specified day from this LocalDate and return a copy of LocalDate. For example, 2019-01-01 minus one day would result in 2018-12-31. This instance is immutable and unaffected by this method call.
What is dos2unix command used for?
dos2unix is a tool to convert text files from DOS line endings (carriage return + line feed) to Unix line endings (line feed). It is also capable of conversion between UTF-16 to UTF-8. Invoking the unix2dos command can be used to convert from Unix to DOS.
How to find the time difference between two dates in Linux?
There’s a solution that almost works: use the %s date format of GNU date, which prints the number of seconds since 1970-01-01 00:00. These can be subtracted to find the time difference between two dates. But the following displays 0 in some locations: Because of daylight savings time, there are only 23 hours between those times.
How do you call a shell function in Unix?
Unix / Linux – Shell Functions 1 Creating Functions. The name of your function is function_name, and that’s what you will use to call it from elsewhere in your scripts. 2 Pass Parameters to a Function. You can define a function that will accept parameters while calling the function. 3 Returning Values from Functions. 4 Nested Functions.
How to get seconds since the epoch in GNU date?
With GNU date, the -d argument can be prepended with @ to indicate “Seconds since the Epoch” format. This came up when using date -d “$death_date – $y years – $m months – $d days” to get a birth date (for genealogy). That command is WRONG.
Why is (date + offset = date) wrong?
That command is WRONG. Months aren’t all the same length, so (date + offset) – offset != date. Ages, in year/month/day, are measures going forwards from the date of birth. Date gives the correct output in both cases, but in the second case you were asking the wrong question.
