Where Is the Linux shadow File?
Linux /etc/shadow password hashes, aging fields and backup files.
Last updated
Linux stores password hashes and aging policy in /etc/shadow, readable only by root, paired with world-readable passwd entries. Useradd writes both files in lockstep.
Edit through passwd and chage, never raw editors on live systems. Shadow backups with trailing dashes restore botched migrations.
Where Linux stores this, by platform
/etc/shadow
Root-only hash and aging database with passwd, group and gshadow beside it. Backups appear as /etc/shadow- after edits. Verify with pwck before logging out. Hash strength follows login.defs and PAM policy.
Frequently asked questions
Why is /etc/shadow unreadable?
Permissions above lock it to root by design. Use sudo cat for audits and passwd for changes.
How do password expiry fields work?
Aging columns in the file above drive chage warnings and lockouts. Set them with chage, not spreadsheet edits.
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