---
name: "update-ca-certificates"
section: "8"
platform: "linux"
package: "ca-certificates"
version: "20250419"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/update-ca-certificates"
---

# update-ca-certificates(8)

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

## NAME

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

## SYNOPSIS

**update-ca-certificates** \[*options*\]

## DESCRIPTION

This manual page documents briefly the **update-ca-certificates** command.

**update-ca-certificates** is a program that manages the collection of TLS certificates for the local machine and generates ca-certificates.crt. ca-certificates.crt is a single-file of concatenated certificates. The collection of individual certificates is stored at /etc/ssl/certs.

The program reads the configuration 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.

Certificates must be in PEM format and have a .crt extension in order to be included by update-ca-certificates. Furthermore, all certificates with a .crt extension found below /usr/local/share/ca-certificates are also included and implicitly trusted.

To add one or more certificates to the machine, copy the certificates in PEM format with the \*.crt extension to /usr/local/share/ca-certificates. There should be one certificate per file, and not multiple certificates in a single file. Then run update-ca-certificates to merge the new certificates into the existing machine store at /etc/ssl/certs.

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 -.

## OPTIONS

A summary of options is included below.

- **-h, --help**

  Show summary of options.

- **-v, --verbose**

  Be verbose. Output **openssl rehash**.

- **-f, --fresh**

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

- **--certsconf**

  Change the configuration file. By default, the file /etc/ca-certificates.conf is used.

- **--certsdir**

  Change the certificate directory. By default, the directory /usr/share/ca-certificates is used.

- **--localcertsdir**

  Change the local certificate directory. By default, the directory /usr/local/share/ca-certificates is used.

- **--etccertsdir**

  Change the /etc certificate directory. By default, the directory /etc/ssl/certs is used.

-

  ## FILES

- */etc/ca-certificates.conf*

  A configuration file.

- */etc/ssl/certs/ca-certificates.crt*

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

- */usr/share/ca-certificates*

  Directory of CA certificates provided by the distribution.

- */usr/local/share/ca-certificates*

  Directory of local CA certificates, with .crt extension, provided by the user.

## SEE ALSO

[**openssl**(1)](/openssl/1.md)

## AUTHOR

This manual page was written by Fumitoshi UKAI \<ukai@debian.or.jp\>, for the Debian project (but may be used by others).