There is no package called devtools in R even after installing devtools - r

Question

I am trying to follow this guide to get R as a usable language in jupyter notebook.
The first step is to run:
install.packages(c('repr', 'IRdisplay', 'evaluate', 'crayon', 'pbdZMQ', 'devtools', 'uuid', 'digest'))
But even after running this command, I still cannot execute the next step:
devtools::install_github('IRkernel/IRkernel')
returning the error:
Error in loadNamespace(name) : there is no package called ‘devtools’
If you look at the comment section of the link I posted someone else seems to also have run into this problem.
Update:
Scott Richie suggested I rerun install.packages('devtools')
this returned:
The downloaded source packages are in
‘/tmp/RtmpgBI8IU/downloaded_packages’
Warning messages:
1: In install.packages("devtools") :
installation of package ‘curl’ had non-zero exit status
2: In install.packages("devtools") :
installation of package ‘openssl’ had non-zero exit status
3: In install.packages("devtools") :
installation of package ‘git2r’ had non-zero exit status
4: In install.packages("devtools") :
installation of package ‘httr’ had non-zero exit status
5: In install.packages("devtools") :
installation of package ‘gh’ had non-zero exit status
6: In install.packages("devtools") :
installation of package ‘usethis’ had non-zero exit status
7: In install.packages("devtools") :
installation of package ‘devtools’ had non-zero exit status
UPDATE 2:
I read up on related threads and was able to get devtools. but I ran into the problem:
> IRkernel::installspec()
Error in IRkernel::installspec() :
jupyter-client has to be installed but “jupyter kernelspec --version” exited with code 1.
This other thread had exited with code 127 and none of the solution did not work in my case. : jupyter-client has to be installed but “jupyter kernelspec --version” exited with code 127