Shell Programming and Scripting

Hi MadeInGermany,
Yes, you're correct. Neither sed -i nor sed -r are included in the standards so I seldom use either of them. I confused the meanings of -i and -r in gsed. (I mistakenly thought gsed's -i performed case insensitive pattern matching and -r created backups. )

On the BSD-based sed that I use on macOS, there is no -r option and the commands:

Code:

Longstring='lots of stuff'
sed -i '1{/^#./! s/.*/'"$Longstring"'/}' filename

would be a request to use 1{/^#./! s/.*/lots of stuff/} as a filename extension on standard input as a backup filename, use filename as an editing command, and process text read from standard input, producing the diagnostic message:

Code:

sed: 1: "filename": invalid command code f

Most of the other commands would fail to perform as expected on macOS (after translating gsed to sed) because the -r option that you want would be interpreted as the extension to be used on the backup files created (not as a request to use EREs instead of BREs when interpreting substitution search patterns).

Looking more closely at the gsed man page and the 1st post in this thread, it would seem that the code presented there could be made to run much more quickly if that script was replaced by:

Code:

Longstring='lots of stuff'
spushd $HOME/somepath

gfind . -depth -name "somefile" -type f -writable -exec gsed -i -r '1{/^#./! s/.*/'"$Longstring"'/}
    s/ts=4/ts=2/g
    s/sw=4/sw=2/g
    s/tab-width: 4/tab-width: 2/g
    s/mode: tcl/mode: _tcl/g'
    s/c-basic-offset: 4/c-basic-offset: 2/g
    s/^\s*(size.*)$/\1/g
    s/^\s*(md.*)$/\1/g
    s/^\s*(rmd.*)$/\1/g
    s/^\s*(sha.*)$/\1/g
    s/^(python.versions.*)$/python.versions 27 36/g' {} +

spopd

which would invoke find once and gsed just a few times (maybe only once depending on the number of pathnames to be processed and the lengths of those pathnames) instead of invoking find 11 times and invoking gsed 11 times for each pathname processed.

But, of course, since I don't have gsed on my system, this suggestion is totally untested.

Some sed versions (BSD ?) have introduced option -E that does the same as the -r in GNU sed.
IMHO the -E is more intuitive because it is used for grep in the same way: use ERE instead of BRE.