Re: Scripting for /bin/ksh

[Todd Gruhn <tgruhn2%gmail.com@localhost>]

Thanks for the link, Lewis. I have never seen this site. I DID find a
book in PDF format
regarding /bin/ksh programming.

My new problem is testing user rank/id.

I want to see if the user is "root"

if (user != root), then print message and die.

This is easy in PERL; I have not done it in /bin/ksh.
I would also like it to execute this test before running the borg command and
spitting out junk...

On Wed, Aug 4, 2021 at 2:47 PM J. Lewis Muir <jlmuir%imca-cat.org@localhost> wrote:
>
> On 08/02, Chavdar Ivanov wrote:
> > On Mon, 2 Aug 2021 at 14:16, Todd Gruhn <tgruhn2%gmail.com@localhost> wrote:
> > >
> > > Thanks for the code Matt.
> > > I will try this.
> > > By 'execute' I mean generate
> > > ${cmd}
> > > then execute/do whatever ${cmd} turns out to be.
> >
> > Depending on the contents of cmd, you might have to use
> >
> > eval ${cmd}
>
> Yes, and there's the rub: the corner cases.  To correctly build up
> a command like this and execute it where spaces and other special
> characters are parsed correctly, you have to shell-quote cmd before
> passing it to eval.  See the "Shell-quoting arbitrary strings" section
> in:
>
>   https://www.etalabs.net/sh_tricks.html
>
> For example, here's a test program that correctly constructs and
> executes two commands, touch and ls, to create and list some
> "interesting" test files:
>
> ----
> #!/bin/ksh
>
> set -e
>
> # https://www.etalabs.net/sh_tricks.html
> quote() {
>   printf %s\\n "$1" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/'/"
> }
>
> # https://dwheeler.com/essays/filenames-in-shell.html
> nl=$(printf '\nX')
> nl=${nl%X}
>
> f1='test_a space'
> f2='test_b"double-quote'
> f3="test_c'single-quote"
> f4="test_d${nl}newline"
> f5='test_e\backslash'
>
> f1_quoted=$(quote "$f1")
> f2_quoted=$(quote "$f2")
> f3_quoted=$(quote "$f3")
> f4_quoted=$(quote "$f4")
> f5_quoted=$(quote "$f5")
>
> cmd="touch $f1_quoted $f2_quoted $f3_quoted $f4_quoted $f5_quoted"
> printf 'cmd: %s\n' "$cmd"
> eval "$cmd"
> cmd="ls -B1 $f1_quoted $f2_quoted $f3_quoted $f4_quoted $f5_quoted"
> printf 'cmd: %s\n' "$cmd"
> eval "$cmd"
> ----
>
> Lewis