Re: Tilde expansion in awk pipes

[b3ak3r]

On 10/6/24 3:44 AM, limited time wrote:
> The command is definitely running in zsh
>
> For example, I can echo various variables set by the shell and they will work 
> as expected.
>
> BEGIN {
>    "echo $ZSH_EXECUTION_STRING" | getline executionstring
>    "echo $ZSH_EVAL_CONTEXT" | getline zshevalcontext
>    "echo $ZSH_VERSION" | getline zshversion
>    print "Execution String =" , executionstring
>    print "Zsh Eval Context =", zshevalcontext
>    print "Zsh Version =", zshversion
> }
>
> ❯ gawk -f script.awk
> Execution String = echo $ZSH_EXECUTION_STRING
> Zsh Eval Context = cmdarg
> Zsh Version = 5.9
>
> ==========
>
> The manpage for sh in my machine says :-
>       sh is a POSIX-compliant command interpreter (shell).It is implemented
>       by re-execing as either bash(1), dash(1), or zsh(1) as determined by the
>       symbolic link located at /private/var/select/sh.If
>       /private/var/select/sh does not exist or does not point to a valid shell,
>       sh will use one of the supported shells.
>
>
> And the link is pointing correctly
>
> ❯ readlink /private/var/select/sh
> /bin/zsh
>
> <snip>

I tested with explicit bash refs (/bin/bash -x -c "echo ~..") and it 
appears the only inconsistency is the "echo ~'/fubar'" case and it's 
across all the usual AWKs (gawk, mawk, oawk, etc.):

--

# command line test:
$ gawk 'BEGIN{cmd="/bin/bash -x -c \"echo ~/fubar\"" ;cmd |getline str 
;close(cmd) ;print str }'

+ echo /home/uesrname/fubar
/home/username/fubar

# awk script test:
$ cat foo.awk
BEGIN{cmd="/bin/bash -x -c \"echo ~/fubar\"" ;cmd |getline str 
;close(cmd) ;print str}

$ gawk -f foo.awk

+ echo '~/fubar'
~/fubar

--

In script form the 'echo' argument string gets *fully quoted* so of 
course it doesn't expand.

-B