Create timestamp variable in bash script

Question

I am trying to build a timestamp variable in a shell script to perform the logging slight easier. I am trying to build the variable at every beginning of the script and have it print out this current time whenever I issue echo $timestamp. It is difficult than I thought. These are the things I've tried:

timestamp="(date +"%T")" echo prints out (date +"%T")

timestamp="$(date +"%T")" echo prints the time when the variable was initialized.

I also tried are just slight changes that didn't work. I need help.

Answer 1

To work on the current timestamp and not the time when your fixed variable is defined, this trick is to use the function and not the variable:

#!/bin/bash

# Define a timestamp function

timestamp() {

  date +"%T" # current time

}

# do something...

timestamp # print timestamp

# do something else...

timestamp # print another timestamp

# continue...

If you don't like this format given by the %T specifier you can combine the other time conversion specifiers accepted through date. For the GNU date, you can find the list of the official documentation here

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