Oh, okay. Now everything is much clearer.
Seeing this, I can understand, for example, why if I run this twice, the
first time I get the output of the 'id' command and the second time the
output of the 'pwd' command.
alias id=pwd;id # id output.
alias id=pwd;id # pwd output.
Thank you again for everything.
Best regards.
El mié, 18 jun 2025 a las 22:23, Chet Ramey (<chet.ra...@case.edu>)
escribió:
> On 6/18/25 4:05 PM, Alberto Millán wrote:
> > First of all, I'd like to thank you for your responses.
> >
> > Okay, now I understand a little better what's going on with recursion.
> >
> > In most cases, I can now see what's wrong, but there's one specific case
> > where I can't quite figure out what's wrong.
> >
> > bash -ic $'alias x=:\nx(){ id;};x' # This case crash.
> > bash -ic $'alias x=:;x(){ id;};x' # This case do not crash.
> >
> > I understand that the crash is caused by recursion, but I don't quite
> > understand why the expansion of '\n' works as expected (crashes), but it
> > doesn't with the semicolon.
>
> The man page says:
>
> "The rules concerning the definition and use of aliases are somewhat
> confusing. Bash always reads at least one complete line of input, and
> all lines that make up a compound command, before executing any of the
> commands on that line or the compound command. Aliases are expanded
> when a command is read, not when it is executed. Therefore, an alias
> definition appearing on the same line as another command does not take
> effect until the shell reads the next line of input, and an alias defi-
> nition in a compound command does not take effect until the shell
> parses and executes the entire compound command."
>
> In this case, the second example is a list, which is a compound command
> (see the `Lists' section in the man page).
>
> Bash parses the entire string passed as the argument to -c before executing
> any of the commands in it.
>
> --
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
> ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
>
