awk print date formats for all letters - lower and upper cases - bash

Question

I'm working on a awk one-liner to get the date command output for all possible characters ( upper and lower case) like below
a Tue | A Tuesday
b Apr | B April
c Tue Apr 14 17:33:37 2020 | C 20
d 14 | D 04/14/20
. . . .
. . . .
z +0530 | Z IST
The below command seems to be syntactically correct, but awk is throwing error.
seq 0 25 | awk ' { d="date \"+" printf("%c",$0+97) " %" printf("%c",$0+97) "\""; d | getline ; print } '
-bash: syntax error near unexpected token `)'
what is wrong with my attempt. Any other awk solution is also welcome.

Answer 1

bash can do this:
for c in {a..z}; do date "+$c %$c | ${c^} %${c^}"; done

Answer 2

Could you please try following(without ASCII numbers using trick).
awk -v s1="\"" '
BEGIN{
num=split("a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z",alphabets,",")
for(i=1;i<=num;i++){
print "date " s1 "+"alphabets[i] " %"alphabets[i] " | " toupper(alphabets[i]) " %"toupper(alphabets[i]) s1
}
}
' | bash
Logical explanation:
Starting awk program and mentioning variable s1 with value ".
Everything we re doing is in BEGIN section of code only.
Using split to create an array named alphabets where all small letters alphabets are stored in it with index of 1,2,3.. and so on.
Now running for loop from 1 to till length of array alphabets.
Now here print command will actually print all the commands(how they should actually run), but this will do only printing of them.
Closing awk command and passing its output to bash will execute the commands and show the output on terminal.

Answer 3

Any time you find youself considering using awk like a shell (i.e. as a tool to call other tools from) you really need to think hard about whether or not it's the right approach.
Using any awk in any shell without the complications of having shell call awk to spawn a subshell to call date and then have getline try to read it and close the pipe, etc. as happens if you try to call date from awk:
$ awk 'BEGIN{for (i=0; i<=25; i++) print c=sprintf("%c",i+97), toupper(c)}' |
while read c C; do date "+$c %$c | $C %$C"; done
a Tue | A Tuesday
b Apr | B April
c Tue Apr 14 09:03:28 2020 | C 20
d 14 | D 04/14/20
e 14 | E E
f f | F 2020-04-14
g 20 | G 2020
h Apr | H 09
i i | I 09
j 105 | J J
k 9 | K K
l 9 | L L
m 04 | M 03
n
| N N
o o | O O
p AM | P P
q q | Q Q
r 09:03:28 AM | R 09:03
s 1586873008 | S 28
t | T 09:03:28
u 2 | U 15
v 14-Apr-2020 | V 16
w 2 | W 15
x 04/14/2020 | X 09:03:28
y 20 | Y 2020
z -0500 | Z CDT

Answer 4

You may want to have this:
awk -v q='"' 'BEGIN{for(i=0;i<=25;i++){
ch=sprintf("%c",i+97)
d="date +%s%s %%%s%s "
sprintf(d, q,ch,ch,q)|getline v;
sprintf(d,q,toupper(ch),toupper(ch),q)|getline v2;
print v "|" v2
close(d)
}}'
Note
you don't need to feed awk by seq 0 25, you can use the BEGIN block
printf does output, if you want the result, use sprintf()
you should close the command after execution
you didn't implement the "uppercase" part
Output:
a Tue|A Tuesday
b Apr|B April
c Tue 14 Apr 2020 03:02:33 PM CEST|C 20
d 14|D 04/14/20
e 14|E %E
f %f|F 2020-04-14
g 20|G 2020
h Apr|H 15
i %i|I 03
j 105|J %J
k 15|K %K
l 3|L %L
m 04|M 02
n |N 396667929
o %o|O %O
p PM|P pm
q 2|Q %Q
r 03:02:33 PM|R 15:02
s 1586869353|S 33
t |T 15:02:33
u 2|U 15
v %v|V 16
w 2|W 15
x 04/14/2020|X 03:02:33 PM
y 20|Y 2020
z +0200|Z CEST