How can I change command and option about 'date' command in bash? - bash

Question

I want to convert this bash command to shell script.
BASH
Input:
date --date="Wed Aug 25 22:37:44 +0900 2021" +"%s"
Output:
1629898664
SHELL
tmp.sh:
function time(a, b, c, d, e) { return date --date="a b c d +0900 e" +"%s" }
{print time($1, $2, $3, $4, $5}
timeline:
Wed Aug 25 22:37:44 2021
Command:
awk -f tmp.sh timeline
Output:
awk: tmp.sh:1: function cvtTime(w) { return date --date="Thu May 14 23:40:52 +0900 2020" +"%s" }
awk: tmp.sh:1: ^ syntax error
What about timeline file has multiple lines? Like:
Wed Aug 25 22:37:44 2021 JACK
Wed Aug 26 22:37:44 2021 EMILY
Wed Aug 27 22:37:44 2021 SAM
I tried:
#!/bin/bash
while read -r line; do
date --date="${1} ${2} ${3} ${4} +0900 ${5}" +"%s"
done
Want:
1629898664 JACK
1629985064 EMILY
1630071464 SAM
But it doesn't work :(

Answer 1

It seems that you want a shell script that is invoked with five command line parameters:
A weekday (in a three-letter format)
A month (in a three-letter format)
Day-of-month
A time expression (HH:MM:SS)
A year (four digits)
(Note that 1. is redundant, it is implied by 2., 3., and 5.)
Hence a somewhat minimal shell script would look sth. like this:
#!/bin/bash
date --date="${1} ${2} ${3} ${4} +0900 ${5}" +"%s"
Of course, this can be greatly improved, e.g., by adding sanity checks for the passed parameters.
In case you want to store the date information in a file so that you can pass a single filename parameter to the script instead (allowing for multiple such lines), the following variation will do:
#!/bin/bash
while read -a i; do
echo $(date --date="${i[0]} ${i[1]} ${i[2]} ${i[3]} +0900 ${i[4]}" +"%s") ${i[5]}
done < ${1}
Note, however, that this version expects an additional name parameter after the date information in each line.
In any event, no need for awk here.