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update /etc/ssl/certs and certificates.crt

see also : c_rehash


update-ca-certificates [options]

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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.



A configuration file.


A single-file version of CA certificates. This hold all CA certificates that you activated in /etc/ca-certificates.conf.


Directory of CA certificates.


Directory of local CA certificates (with .crt extension).

see also

c_rehash ,


This manual page was written by Fumitoshi UKAI <ukai[:at:]debian.or[:dot:]jp>, for the Debian project (but may be used by others).

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