Re: [PATCH] df: new options

[Bernhard Voelker]

On 2/11/23 11:03, Gunnar Lindholm wrote:
> > 10 feb. 2023 kl. 23:09 skrev Bernhard Voelker <mail@bernhard-voelker.de>:
> > On 2/3/23 20:58, Gunnar Lindholm wrote:
> > > +With the @option{-b} and @option{-f} options one can use the exit status to
> > > +verify the available space (in bytes or percentage) with a command like
> > > +@samp{if df -b 640000 /var/log ; then echo "That is big enough for everyone"; 
> > > fi}

> > a) The functionality can easily be achieved via scripting, e.g. using the 
> > --output option
> > and sed(1):

> >   $ if test 80 -gt `df --output=pcent / | sed '1d;s/%//'`; then echo FINE; else 
> > echo TOO_FULL; fi
> >   TOO_FULL

> [...] it as an advantage to keep sed out of if-statements and make them less 
> complicated.

That was just one example with sed(1); there are dozens of alternatives, 
including pure shell
pattern replacement.

Probably one would wrap that into an alias, a function or a wrapper shell 
script anyway ...

  $ cat ~/bin/df-pct-lower
  #!/bin/sh

  x="$( df --output=pcent "$1" | sed '1d;s/[% ]*//g' )" \
    && test "$x" \
    || { echo "$0: error: failed to determine df percentage: '$1'" >&2; exit 1; 
}

  test "$x" -lt "$2"

so the details don't show up in the business logic:

  $ df-pct-lower / 80; echo $?
  1

  $ df-pct-lower / 90; echo $?
  0

Have a nice day,
Berny