Bash script with a loop [duplicate] - bash

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Looping over pairs of values in bash [duplicate]
(6 answers)
Closed 4 years ago.
I'm trying to create bash script to generate certificates via openssl in a loop with different parameters.
Of course it's easy to write many lines of code with different parameters, something like:
#!/bin/bash
openssl req -x509 -sha256 -nodes -days 1 -newkey rsa:1024 -keyout private1024_1.key -out RSA_1024_1_SHA256.crt -subj "/C=XX/ST=XXX/L=XXX /O=xxx/OU=xxx/CN=xx.xx/emailAddress=xx#xx.xx"
openssl req -x509 -sha256 -nodes -days 3 -newkey rsa:1024 -keyout private1024_3.key -out RSA_1024_3_SHA256.crt -subj "/C=XX/ST=XXX/L=XXX /O=xxx/OU=xxx/CN=xx.xx/emailAddress=xx#xx.xx"
but I don't think that's a good practice.
So I would like to create some loops with variables where I can set:
number of days;
type of rsa(1024/2048/4096);
name of private key according to type of rsa and numbers of day;
name of certificate according to type of rsa and numbers of day.
About -subj I think just make a separate table of variables and change them if need. I'm not so close with coding, but hope that it's possible to realize this idea with loops.
I will be grateful for any tips or patterns.
Realize next(and it's working):
#!/bin/bash
# Certificate details; replace items in angle brackets with your own info
subj="
C=XX
ST=XXX
O=XXXX
localityName=XXX xx
commonName=xxx.xx
organizationalUnitName=xxx xx
emailAddress=test#xxx.xx
"
declare -a days=(1 3 5 10 15 30 365)
declare -a rsatype=(1024 2048 4096)
declare -a sha=(sha1 md5 sha256 sha512)
dd=7
rst=3
shat=4
for ((i = 0; i < dd; i++))
do
for((j = 0; j < rst; j++))
do
for((k = 0; k < shat; k++))
do
keyout=private${rsatype[$j]}_${days[$i]}.key
out=RSA_${rsatype[$j]}_${days[$i]}_${sha[$k]}.crt
openssl req -x509 -${sha[$k]} -nodes -days ${days[$i]} -newkey rsa:"${rsatype[$j]}" -keyout "$keyout" -out "$out" -subj "$(echo -n "$subj" | tr "\n" "/")"
done
done
done

Answer 1

You can just use two arrays for the number of days and rsa type, while the name of the private key and the name of certificate are determined from the data of the two arrays. Then you iterate a loop over the array elements.
Example:
#!/bin/bash
declare -a days=(1 3)
declare -a rsatype=(1024 2048)
tot=2
for ((i = 0; i < tot; i++))
do
keyout=private${rsatype[$i]}_${days[$i]}.key
out=RSA_${rsatype[$i]}_${days[$i]}_SHA256.crt
openssl req -x509 -sha256 -nodes -days ${days[$i]} -newkey rsa:${rsatype[$i]} \
-keyout $keyout -out $out \
-subj "/C=XX/ST=XXX/L=XXX /O=xxx/OU=xxx/CN=xx.xx/emailAddress=xx#xx.xx"
done