How to install libpng-dev on Mac
Processes not started from a shell may not inherit environment variables from that shell. Start R in Terminal to make sure that your R process inherits PATH
from the Terminal shell where you have run which
. Something like
$ Rscript -e "install.packages(\"png\")"
should work, though you may need to select a CRAN mirror, in which case the above will throw an error. You can do that in the install.packages
call, like so:
$ Rscript -e "install.packages(\"png\", repos = \"https://cloud.r-project.org\")"
or by setting a global option, like so:
$ Rscript -e "options(repos = \"https://cloud.r-project.org\"); install.packages(\"png\")"
For details, see the R for macOS FAQ and ?options
.