Enable shadow passwords for users.
The pwconv command is used to enable shadow passwords for users. In Linux, user and group passwords are stored in files named passwd and group in the /etc directory. Since these files must be readable by everyone for system operations, this presents a security risk. Shadow passwords move the encrypted passwords to the shadow and gshadow files in the /etc directory, which are readable only by the system administrator. The original password fields are replaced with "x", effectively strengthening system security.
pwconv
cat /etc/passwd | grep test
test:x:3001:3001::/home/test:/bin/sh
At this point, you can see the password field is x.
cat /etc/shadow | grep test
test:$6$nYOEWamm$bz07nlv/.RgJufb3FAqJJeULfwybzgxmrWqbk7O4vI0KsT6N.ujrh6dDIUcAJdfjksyuyAFDPIngZeD3cgcf.0:15022:0:99999:7:::