I came across a weird line in a shell script:
: ${parameter:=word}
It is so weird that I don't even know how to search for further information. Fortunately, I found a post after searching bash colon. It is a built-in utility which simply exits with 0. In the other words …
In a shell script, file descriptor 0 stands for stdin, file descriptor 1
stands for stdout, and file descriptor 2 stands for stderr. In addition,
programmers can open, close, or duplicate file descriptors with the
exec built-in command and the I/O redirection operator:
| Syntax | Description |
|---|---|
exec $fd< "${filepath}" |
Open … |
I would like to launch ssh-agent and add my private key at the beginning of
my shell script and stop it before leaving the shell script. How do I
guarantee that ssh-agent will be shutted down properly? What will happen
if the user press Ctrl-C or even kill the shell …
