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How to check if a date is valid in Bash?
If the date is invalid, an error message is printed to STDERR and date exits with an error status. If the date is valid, it prints the date on STDOUT and exits with a success status. Because of this, date -d “$date” can be used directly in a bash if statement.
Why do I need to check format in Bash?
You need the two checks because : The format string uses the codes from the date command but does not include the ‘+’ The function returns 0 if the provided date matches the given format, otherwise it returns 1 First, check the form of the input using the regex.
When to use date-D$ date in Bash?
If the date is valid, it prints the date on STDOUT and exits with a success status. Because of this, date -d “$date” can be used directly in a bash if statement. The first wrinkle is that to prevent printing a message for valid dates, you need to redirect STDOUT to /dev/null using >/dev/null.
Why do you need two checks in Bash?
It consists in combining 2 checks : You need the two checks because : The format string uses the codes from the date command but does not include the ‘+’ The function returns 0 if the provided date matches the given format, otherwise it returns 1 First, check the form of the input using the regex.
How to calculate date of X days ago in Bash?
I’m trying to calculate the date for a dynamic number of days ago in a bash script. How can I use my argument value in this formula? An expert in bash scripting (not me) can probably explain why this has happen.
Why does date accept an empty string as a date?
The second wrinkle is that date accepts an empty string as a valid date without complaint. In most cases, that should mean that your user didn’t enter a date when they should have.
What does up to date mean in Git?
When git status says up-to-date, it means “up-to-date with the branch that the current branch tracks”, which in this case means “up-to-date with the local ref called origin/master”.