envsubst
seems exactly like something I wanted to use, but -v
option surprised me a bit.
While envsubst < template.txt
was working fine, the same with option -v
was not working:
$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.1 (Maipo)
$ envsubst -V
envsubst (GNU gettext-runtime) 0.18.2
Copyright (C) 2003-2007 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Written by Bruno Haible.
As I wrote, this was not working:
$ envsubst -v < template.txt
envsubst: missing arguments
$ cat template.txt | envsubst -v
envsubst: missing arguments
I had to do this to make it work:
TEXT=`cat template.txt`; envsubst -v "$TEXT"
Maybe it helps someone.