Linux Service Account Creation

svc_account_creation.txt

useradd username \
  --system \
  --shell /bin/nologin \
  --comment "Description of account" \
  --expiredate 1 # block all authentication \
  --create-home # or --no-create-home \
  --home /home/dir
  
# Or, short version (w/ home directory)
useradd username -r -s /bin/nologin -c "description" -e 1 -m -d /home/dir
# No home directory
useradd username -r -s /bin/nologin -c "description" -e 1 -M
  
# Resulting entry in /etc/passwd
username:x:998:997:Description of account:/home/username:/bin/nologin

# Resulting entry in /etc/shadow (password already locked)
username:!:18420::::::