不设置变量$ip_choice
的情况下,能否将其与数字进行比较?
#!/bin/bash
ip_choice=999
while ! (( $ip_choice <= 233 ))
do
read -p "Enter a valid IP (1-256): " ip_choice
done
它的工作方式就像这样 - 只是我想知道是否有更加优雅的可能性 :-).
#!/bin/bash
while read -r -p "Enter a valid IP (1-256): " ip_choice; do
(( ip_choice >= 1 && ip_choice <= 256 )) && break
done
echo "${ip_choice}"
$ ./t.sh
Enter a valid IP (1-256): -1
Enter a valid IP (1-256): 0
Enter a valid IP (1-256): 257
Enter a valid IP (1-256): abc
Enter a valid IP (1-256): 20
20
until
:until ((ip_choice >=1 && ip_choice <= 256)); do
read -p "Enter a valid IP (1-256): " ip_choice;
done
引用自help until
:
until: until COMMANDS; do COMMANDS; done
Execute commands as long as a test does not succeed. Expand and execute COMMANDS as long as the final command in the `until' COMMANDS has an exit status which is not zero. Exit Status: Returns the status of the last command executed.
例如:
$ until ((ip_choice >=1 && ip_choice <= 256)); do
> read -p "Enter a valid IP (1-256): " ip_choice;
> done
Enter a valid IP (1-256): 0
Enter a valid IP (1-256): 298
Enter a valid IP (1-256): 242