systemctl does not appear to have a mechanism for specifying when to color the output. A quick solution would be to shim isatty(3) to always return true, thus tricking systemctl into thinking stdout is interactive. Namely you could do:
# echo "int isatty(int fd) { return 1; }" | gcc -O2 -fpic -shared -ldl -o isatty.so -xc - # LD_PRELOAD=./isatty.so watch -n300 --color systemctl status plexmediaserver The -xc - at the end of the gcc command tells gcc to compile C code (-xc) from stdin (-). The rest of the flags tell gcc to create a shared object file named isatty.so. Note that this could very well break other programs which rely on isatty to return a legitimate value. It however appears to be fine for systemctl as isatty appears to be solely used for the purpose of determining if it should color its output.