Wednesday, 20 July 2022

Today I Learned - Shorter redirection, what's not to like ?

So I write a lot of scrips for Bash and Zsh, and often make use of redirection where, for example, I generate a variable by running another command within parentheses.

As a specific example, I'd query my Floating IP and persist it to a text file for future use: -

ic is floating-ips --output JSON | jq -r '.[].address' > ~/floating_ip.txt

Later on, I'd look to use that Floating IP for, for example, a SSH connection, as follows: -

export floating_ip=$(cat floating_ip.txt)

ssh root@$floating_ip

Authorized uses only. All activity may be monitored and reported.

root@163.61.95.34's password:

However, one of my colleague's did point out that I could reduce the number of characters typed when setting the floating_ip variable: -

export floating_ip=$(< floating_ip.txt)

See, that saves a whole two characters ....

Mind you, I can also reduce things further via: -

ssh root@$(cat floating_ip.txt)

I love shelling !

No comments:

Reminder - how to split strings in a shell script

There's almost certainly 73 different ways to do this, but this worked for me The problem to be solved ... I have a string containing th...