Date: Fri, 5 Mar 2021 23:15:27 -0600 From: Kyle Evans <kevans@freebsd.org> To: freebsd@dreamchaser.org Cc: Kyle Evans <kevans@freebsd.org>, FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: sed -i empty argument compatibility issue Message-ID: <CACNAnaGhGpjO0BzFskJketcnvi5%2BsjOD9N-jTffK_Ejnpt%2BzXQ@mail.gmail.com> In-Reply-To: <f89c2931-ae39-37c4-9638-f0ab39884c3f@dreamchaser.org> References: <9178f6c5-631a-c2c2-c6b1-8def94a3397b@dreamchaser.org> <CACNAnaGNj55KkSEZOoEqtMVOXtFpk5Ek9tEKJJYARWUGgpwCcw@mail.gmail.com> <f89c2931-ae39-37c4-9638-f0ab39884c3f@dreamchaser.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, Mar 5, 2021 at 11:12 PM Gary Aitken <freebsd@dreamchaser.org> wrote:
>
> On 3/5/21 9:39 PM, Kyle Evans wrote:
> > On Fri, Mar 5, 2021 at 3:03 PM Gary Aitken <freebsd@dreamchaser.org> wrote:
> >>
> >> I'm trying to come up with a fix for a script in a port which invokes sed.
> >> The port comes from a linux environment, and the offending line looks like this:
> >> (This is in a cMake file.)
> >>
> >> COMMAND sed -i "/^# /d" "${outfile}"
> >>
> >> The issue is that linux sed expects the -I or -i extension modifier to
> >> immediately follow the -i. In the above line, the extension is deliberately
> >> missing to provide in-place editing.
> >>
> >> fbsd expects the extension to be separated from the -i by whitespace, or
> >> doesn't work properly when it is empty or immediately follows the -i:
> >>
> >> $ !ls
> >> ls -lt temp.tmp*
> >> -rw------- 1 garya garya 86 Mar 5 13:15 temp.tmp
> >> -rw------- 1 garya garya 86 Mar 5 13:15 temp.tmp_org
> >> $ sed -ifoo "/^# /d" temp.tmp (works on both fbsd & linux))
> >> $ !ls
> >> ls -lt temp.tmp*
> >> -rw------- 1 garya garya 30 Mar 5 13:48 temp.tmp
> >> -rw------- 1 garya garya 86 Mar 5 13:15 temp.tmp_org
> >> -rw------- 1 garya garya 86 Mar 5 13:15 temp.tmpfoo
> >> $ cp -p temp.tmp_org temp.tmp
> >> $ sed -i"" "/^# /d" temp.tmp (works on linux but not fbsd)
> >> sed: 1: "temp.tmp": undefined label 'emp.tmp'
> >> $ sed -i "" "/^# /d" temp.tmp (works on fbsd but not linux)
> >> $ !ls
> >> ls -lt temp.tmp*
> >> -rw------- 1 garya garya 30 Mar 5 13:49 temp.tmp
> >> -rw------- 1 garya garya 86 Mar 5 13:15 temp.tmp_org
> >> -rw------- 1 garya garya 86 Mar 5 13:15 temp.tmpfoo
> >>
> >> So fbsd works with '-i ""' but linux requires '-i""'
> >>
> >> Does anyone know a work-around for this problem?
> >>
> >
> > My personal favorite trick to bridge the gap here was, as I recall:
> >
> > sed -i'' '' 's/../.../' ${file}
> >
> > IIRC those sed's with an optional backup suffix (Linux, OpenBSD) will
> > accept the immediately following empty string and accept the next
> > empty word as an empty command, while our getopt will effectively
> > ignore the rest of the -i word and use the following optarg as usual.
>
> Unfortunately, times appear to have changed, at least on ubuntu-18.04:
>
> $ sed -i'' '' "/^# /d" temp.tmp
> sed: can't read /^# /d: No such file or directory
>
Oh, sorry. Try slapping with an -e:
$ sed -i'' '' -e "/^# /d" temp.tmp
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CACNAnaGhGpjO0BzFskJketcnvi5%2BsjOD9N-jTffK_Ejnpt%2BzXQ>