Man page 8 : update-ca-certificates

update-ca-certificates - update /etc/ssl/certs and certificates.crt

update-ca-certificates [ options ]

This manual page documents briefly the

update-ca-certificates commands. This manual page was written for the Debian distribution.

update-ca-certificates is a program that updates the directory /etc/ssl/certs to hold SSL certificates and generates certificates.crt, a concatenated single-file list of certificates.

It reads the file /etc/ca-certificates.conf. Each line gives a pathname of a CA certificate under /usr/share/ca-certificates that should be trusted. Lines that begin with "#" are comment lines and thus ignored. Lines that begin with "!" are deselected, causing the deactivation of the CA certificate in question.

Furthermore all certificates found below /usr/local/share/ca-certificates are also included as implicitly trusted.

Before terminating, update-ca-certificates invokes run-parts on /etc/ca-certificates/update.d and calls each hook with a list of certificates: those added are prefixed with a +, those removed are prefixed with a -.

A summary of options is included below.

-h, --help

    Show summary of options.

-v, --verbose

    Be verbose. Output c_rehash.

-f, --fresh

    Fresh updates. Remove symlinks in /etc/ssl/certs directory.

• /etc/ca-certificates.conf
      A configuration file.
• /etc/ssl/certs/ca-certificates.crt
      A single-file version of CA certificates. This hold all CA certificates that you activated in /etc/ca-certificates.conf.
• /usr/share/ca-certificates
      Directory of CA certificates. /usr/local/share/ca-certificatesDirectory of local CA certificates.

R c_rehash (1),

This manual page was written by Fumitoshi UKAI <>, for the Debian project (but may be used by others).