'\" t .\" Man page generated from reStructuredText .\" by the Docutils 0.22.4 manpage writer. . . .nr rst2man-indent-level 0 . .de1 rstReportMargin \\$1 \\n[an-margin] level \\n[rst2man-indent-level] level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] - \\n[rst2man-indent0] \\n[rst2man-indent1] \\n[rst2man-indent2] .. .de1 INDENT .\" .rstReportMargin pre: . RS \\$1 . nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin] . nr rst2man-indent-level +1 .\" .rstReportMargin post: .. .de UNINDENT . RE .\" indent \\n[an-margin] .\" old: \\n[rst2man-indent\\n[rst2man-indent-level]] .nr rst2man-indent-level -1 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]] .in \\n[rst2man-indent\\n[rst2man-indent-level]]u .. .TH "borg" "1" "2026-08-29" "" "borg backup tool" .SH Name borg \- deduplicating and encrypting backup tool .SH SYNOPSIS .sp borg [common options] [options] [arguments] .SH DESCRIPTION .\" we don't include the README.rst here since we want to keep this terse. . .sp BorgBackup (short: Borg) is a deduplicating backup program. Optionally, it supports compression and authenticated encryption. .sp The main goal of Borg is to provide an efficient and secure way to back up data. The data deduplication technique used makes Borg suitable for daily backups since only changes are stored. The authenticated encryption technique makes it suitable for backups to targets not fully trusted. .sp Borg stores a set of files in an \fIarchive\fP\&. A \fIrepository\fP is a collection of \fIarchives\fP\&. The format of repositories is Borg\-specific. Borg does not distinguish archives from each other in any way other than their name, it does not matter when or where archives were created (e.g., different hosts). .SH EXAMPLES .SS A step\-by\-step example .INDENT 0.0 .IP 1. 3 Before a backup can be made, a repository has to be initialized: .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo repo\-create \-\-encryption=aes256\-ocb .EE .UNINDENT .UNINDENT .IP 2. 3 Back up the \fB~/src\fP and \fB~/Documents\fP directories into an archive called \fIdocs\fP: .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo create docs ~/src ~/Documents .EE .UNINDENT .UNINDENT .IP 3. 3 The next day, create a new archive using the same archive name: .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo create \-\-stats docs ~/src ~/Documents .EE .UNINDENT .UNINDENT .sp This backup will be much quicker and much smaller, since only new, never\-before\-seen data is stored. The \fB\-\-stats\fP option causes Borg to output statistics about the newly created archive such as the deduplicated size (the amount of unique data not shared with other archives): .INDENT 3.0 .INDENT 3.5 .sp .EX Repository: /path/to/repo Archive name: docs Archive fingerprint: 74efb3f0c9c05f8b7c822ba859919b480578a3457fd4965c2cee64fbdb631262 Time (nominal): Fri, 2026\-08\-28 12:24:24 +0200 Time (start): Fri, 2026\-08\-28 12:24:24 +0200 Time (end): Fri, 2026\-08\-28 12:24:24 +0200 Duration: 0.008 seconds Number of files: 100 Original size: 1.99 MB Deduplicated size: 703 B Time spent in hashing: 0.000 seconds Time spent in chunking: 0.000 seconds Added files: 1 Unchanged files: 99 Modified files: 0 Error files: 0 Files changed while reading: 0 \&... .EE .UNINDENT .UNINDENT .sp (some more lines with statistics about the repository store accesses follow) .IP 4. 3 List all archives in the repository (the first column is the beginning of the archive ID): .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo repo\-list 3affe017 Fri, 2026\-08\-28 12:24:10 +0200 docs user machine 74efb3f0 Fri, 2026\-08\-28 12:24:24 +0200 docs user machine .EE .UNINDENT .UNINDENT .IP 5. 3 List the contents of the first archive: .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo list aid:3affe017 drwxr\-xr\-x user group 0 Fri, 2026\-08\-28 12:22:30 +0200 home/user/Documents \-rw\-r\-\-r\-\- user group 7961 Fri, 2026\-08\-28 12:22:30 +0200 home/user/Documents/Important.doc \&... .EE .UNINDENT .UNINDENT .IP 6. 3 Restore the first archive by extracting the files relative to the current directory: .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo extract aid:3affe017 .EE .UNINDENT .UNINDENT .IP 7. 3 Delete the first archive (please note that this does \fBnot\fP free repository disk space): .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo delete aid:3affe017 .EE .UNINDENT .UNINDENT .sp If you use an archive NAME (and not an archive ID), Borg will abort if the name matches multiple archives (as with the two \fIdocs\fP archives here); use \fBaid:\fP to delete one specific archive, or \fB\-a PATTERN\fP to delete multiple archives. Always use \fB\-\-dry\-run\fP and \fB\-\-list\fP first! .IP 8. 3 Recover disk space by removing objects that are not referenced by any archive any more: .INDENT 3.0 .INDENT 3.5 .sp .EX $ borg \-r /path/to/repo compact \-v .EE .UNINDENT .UNINDENT .UNINDENT .sp \fBNote:\fP .INDENT 0.0 .INDENT 3.5 Borg is quiet by default (it defaults to WARNING log level). You can use options like \fB\-\-progress\fP or \fB\-\-list\fP to get specific reports during command execution. You can also add the \fB\-v\fP (or \fB\-\-verbose\fP or \fB\-\-info\fP) option to adjust the log level to INFO to get other informational messages. .UNINDENT .UNINDENT .SH NOTES .SS Positional Arguments and Options: Order matters .sp Borg only supports taking options (\fB\-s\fP and \fB\-\-progress\fP in the example) either to the left or to the right of all positional arguments (\fBarchive\fP and \fBpath\fP in the example), but not in between them: .INDENT 0.0 .INDENT 3.5 .sp .EX borg create \-s \-\-progress archive path # good and preferred borg create archive path \-s \-\-progress # also works borg create \-s archive path \-\-progress # works, but ugly borg create archive \-s \-\-progress path # BAD .EE .UNINDENT .UNINDENT .sp This is due to a problem in the argparse module: \% .SS Repository URLs .sp \fBLocal filesystem\fP (or locally mounted network filesystem): .sp \fB/path/to/repo\fP — filesystem path to the repository directory (absolute path) .sp \fBpath/to/repo\fP — filesystem path to the repository directory (relative path) .sp Also, paths like \fB~/path/to/repo\fP or \fB~other/path/to/repo\fP work (this is expanded by your shell). .sp Note: You may also prepend \fBfile://\fP to an absolute filesystem path to use URL style, e.g. \fBfile:///abs/path/to/repo\fP\&. This only works for absolute paths — \fBfile://rel/path\fP is rejected; use a plain relative path (see above) instead. .sp Note: UNC paths (\fB//server/share/path\fP, \fB\e\eserver\eshare\epath\fP) are not supported — mount the share (on Windows: map it to a drive letter, e.g. \fBnet use X: \e\eserver\eshare\fP) and use the mounted path instead. .sp \fBRemote repositories\fP accessed via SSH \% (REST http over stdio): .sp \fBrest://user@host:port//abs/path/to/repo\fP — absolute path .sp \fBrest://user@host:port/rel/path/to/repo\fP — path relative to the remote login directory .sp \fBRemote repositories\fP accessed via SSH \% (legacy borg RPC protocol): .sp \fBssh://user@host:port//abs/path/to/repo\fP — absolute path .sp \fBssh://user@host:port/rel/path/to/repo\fP — path relative to the remote login directory .sp For current (non\-legacy) repositories, \fBssh://\fP is rejected; use \fBrest://\fP instead, which can also tunnel over ssh (see above). \fBssh://\fP remains available only for legacy borg 1.x repositories, e.g. via \fBborg transfer \-\-from\-borg1 \-\-other\-repo ssh://...\fP\&. .sp \fBRemote repositories\fP accessed via SFTP: .sp \fBsftp://user@host:port//abs/path/to/repo\fP — absolute path .sp \fBsftp://user@host:port/rel/path/to/repo\fP — path relative to the remote login directory .sp For REST, SSH and SFTP URLs, the \fBuser@\fP and \fB:port\fP parts are optional, but the path is required: a URL without one, e.g. \fBrest://host\fP or \fBrest://host/\fP, is rejected. Mind the difference between one and two slashes after the host: one slash means a path relative to the directory the remote login lands in (usually the remote user\(aqs home directory), two slashes mean an absolute path. .sp \fBRemote repositories\fP accessed directly via HTTP(S), talking to a borgstore REST server: .sp \fBhttp://host:port\fP — plain HTTP .sp \fBhttps://user:password@host:port\fP — HTTPS, optionally with credentials embedded in the URL .sp For \fBhttp://\fP and \fBhttps://\fP URLs, \fBuser:password@\fP and \fB:port\fP are optional. Authentication is HTTP Basic auth: credentials come from the URL if given, otherwise from the \fBBORGSTORE_REST_USERNAME\fP / \fBBORGSTORE_REST_PASSWORD\fP environment variables; prefer \fBhttps://\fP over \fBhttp://\fP whenever credentials are used, since Basic auth sends them on every request. A URL path after the host is optional and, unlike \fBrest://\fP, is not a remote filesystem path — it does not follow the one\-vs\-two\-slash rule above and is only needed to reach the server through a reverse proxy mounted below a sub\-path. .sp \fBRemote repositories\fP accessed via rclone: .sp \fBrclone:remote:path\fP — see the rclone docs for more details about \fBremote:path\fP\&. .sp \fBRemote repositories\fP accessed via S3: .sp \fB(s3|b2):[(profile|(access_key_id:access_key_secret))@][scheme://hostname[:port]]/bucket/path\fP — see the boto3 docs for more details about credentials. .sp If you are connecting to AWS S3, \fB[schema://hostname[:port]]\fP is optional, but \fBbucket\fP and \fBpath\fP are always required. \fIscheme\fP is usually \fIhttps\fP here, hostname and optional port refer to your S3/B2 server, if that is not Amazon\(aqs. .sp Note: There is a known issue with some S3\-compatible services, e.g., Backblaze B2. If you encounter problems, try using \fBb2:\fP instead of \fBs3:\fP in the URL. .sp If you frequently need the same repository URL, it is a good idea to set the \fBBORG_REPO\fP environment variable to set a default repository URL: .INDENT 0.0 .INDENT 3.5 .sp .EX export BORG_REPO=\(aqrest://user@host:port/rel/path/to/repo\(aq .EE .UNINDENT .UNINDENT .sp Then simply omit the \fB\-\-repo\fP option when you want to use the default — it will be read from BORG_REPO. .SS Repository Locations / Archive Names .sp Many commands need to know the repository location; specify it via \fB\-r\fP/\fB\-\-repo\fP or use the \fBBORG_REPO\fP environment variable. .sp Commands that need one or two archive names usually take them as positional arguments. .sp Commands that work with an arbitrary number of archives usually accept \fB\-a ARCH_GLOB\fP\&. .sp Archive names must not contain the \fB/\fP (slash) character. For simplicity, also avoid spaces or other characters that have special meaning to the shell or in a filesystem (\fBborg mount\fP uses the archive name as a directory name). .\" This file is the man page variant of docs/usage/usage_general.rst.inc and must .\" not define the labels that variant defines - otherwise Sphinx warns about .\" duplicate labels. archive-specification.rst.inc carries its label inside the .\" file, so skip that line here. . .SS Specifying an archive .sp How to refer to an archive depends on whether you use archive series or not. .sp \fBBy ID:\fP if you use archive series, many or all archives will have the same name, thus you need to refer to a single archive by its archive ID (see \fBborg repo\-list\fP output): .INDENT 0.0 .INDENT 3.5 .sp .EX borg info aid:f7dea078 .EE .UNINDENT .UNINDENT .sp The \fBaid:\fP prefix does a prefix match on the archive ID (the hex representation of the archive fingerprint). You only need to give enough hex digits to uniquely identify the archive. This is useful when archive names are ambiguous or when you want to refer to an archive by its immutable ID. .sp \fBBy name:\fP if you don\(aqt use archive series, but do it old\-style by giving every archive a unique name, you can refer to an archive by its name: .INDENT 0.0 .INDENT 3.5 .sp .EX borg info my\-backup\-202512312359 .EE .UNINDENT .UNINDENT .sp For more details on archive matching patterns (including shell\-style globs, regular expressions, and matching by user/host/tags), see \fIborg_match\-archives\fP\&. .SS Logging .sp Borg writes all log output to stderr by default. However, output on stderr does not necessarily indicate an error. Check the log levels of the messages and the return code of borg to determine error, warning, or success conditions. .sp If you want to capture the log output to a file, just redirect it: .INDENT 0.0 .INDENT 3.5 .sp .EX borg create \-\-repo repo archive myfiles 2>> logfile .EE .UNINDENT .UNINDENT .sp Custom logging configurations can be implemented via BORG_LOGGING_CONF. .sp The log level of the built\-in logging configuration defaults to WARNING. This is because we want Borg to be mostly silent and only output warnings, errors, and critical messages unless output has been requested by supplying an option that implies output (e.g., \fB\-\-list\fP or \fB\-\-progress\fP). .sp Log levels: DEBUG < INFO < WARNING < ERROR < CRITICAL .sp Use \fB\-\-debug\fP to set the DEBUG log level — this prints debug, info, warning, error, and critical messages. .sp Use \fB\-\-info\fP (or \fB\-v\fP or \fB\-\-verbose\fP) to set the INFO log level — this prints info, warning, error, and critical messages. .sp Use \fB\-\-warning\fP (default) to set the WARNING log level — this prints warning, error, and critical messages. .sp Use \fB\-\-error\fP to set the ERROR log level — this prints error and critical messages. .sp Use \fB\-\-critical\fP to set the CRITICAL log level — this prints only critical messages. .sp While you can set miscellaneous log levels, do not expect every command to produce different output at different log levels — it\(aqs merely a possibility. .sp \fBWarning:\fP .INDENT 0.0 .INDENT 3.5 Options \fB\-\-critical\fP and \fB\-\-error\fP are provided for completeness, their usage is not recommended as you might miss important information. .UNINDENT .UNINDENT .SS Return codes .sp Borg can exit with the following return codes (rc): .TS box center; l|l. T{ Return code T} T{ Meaning T} _ T{ 0 T} T{ success (logged as INFO) T} _ T{ 1 T} T{ generic warning (operation reached its normal end, but there were warnings \- you should check the log; logged as WARNING) T} _ T{ 2 T} T{ generic error (such as a fatal error or a local/remote exception; the operation did not reach its normal end; logged as ERROR) T} _ T{ 3..99 T} T{ specific error (see below; logged as ERROR) T} _ T{ 100..127 T} T{ specific warning (see below; logged as WARNING) T} _ T{ 128+N T} T{ terminated by signal N (e.g. 130 == SIGINT, Ctrl+C, or kill \-2; logged as ERROR) T} .TE .sp If you use \fB\-\-show\-rc\fP, the return code is also logged at the indicated level as the last log entry. .sp Borg categorizes return codes into groups and exits with the more severe group: signals (rc 128+N) are more severe than errors (rc 2 and 3..99), which take precedence over warnings (rc 1 and 100..127), and lastly success (rc 0). .sp Within the signal and error groups, the first signal or error determines the final return code. Within the warning group, Borg returns the specific warning code (rc 100..127) if there were one or more warnings of the same kind. If warnings of different kinds occurred, Borg returns the generic warning code (rc 1) instead. All errors and warnings are still logged individually. .sp Borg 2 exits with specific error (rc 3..99) and warning (rc 100..127) codes by default. If you want Borg 2 to always exit with the generic error (rc 2) or generic warning (rc 1) code instead (like Borg 1 did), set the \fBBORG_EXIT_CODES=legacy\fP environment variable. .sp For a list of all specific error and warning codes, see \fImsgid\fP\&. .SS Configuration Precedence .INDENT 0.0 .INDENT 3.5 From lowest to highest: .INDENT 0.0 .INDENT 3.5 .INDENT 0.0 .IP 1. 3 Defaults defined in the source code. .IP 2. 3 Default config file (\fB$BORG_CONFIG_DIR/default.yaml\fP). .IP 3. 3 \fB\-\-config\fP file(s) (in the order given). .IP 4. 3 Full config environment variable: (\fBBORG_CONFIG\fP). .IP 5. 3 Environment variables (e.g. \fBBORG_LOG_LEVEL\fP). .IP 6. 3 Command\-line arguments in order left to right (might include config files). .UNINDENT .UNINDENT .UNINDENT .UNINDENT .UNINDENT .SS Configuration files .sp Borg supports reading options from YAML configuration files. This is implemented via jsonargparse \% and works for all options that can also be set on the command line. .INDENT 0.0 .TP .B Default configuration file \fB$BORG_CONFIG_DIR/default.yaml\fP is loaded automatically on every Borg invocation if it exists. You do not need to pass \fB\-\-config\fP explicitly for this file. .TP .B \fB\-\-config PATH\fP Load additional options from the YAML file at \fIPATH\fP\&. Options in this file take precedence over the default config file but are overridden by explicit command\-line arguments. This option can be used multiple times, with later files overriding earlier ones. .TP .B \fB\-\-print_config\fP Print the current effective configuration (all options in YAML format) to stdout and exit. This reflects the merged result of the default config file, any \fB\-\-config\fP file, environment variables, and command\-line arguments. The output can be used as a starting point for a config file. .sp \fB\-\-print_config\fP is a common option, so it must be given \fIbefore\fP the subcommand name — the subcommand\(aqs own options still show up in the output. .TP .B File format Config files are YAML documents. Top\-level keys are option names (without leading \fB\-\-\fP and with \fB\-\fP replaced by \fB_\fP). Nested keys correspond to subcommands. .sp Example \fBdefault.yaml\fP: .INDENT 7.0 .INDENT 3.5 .sp .EX # apply to all borg commands: log_level: info show_rc: true # options specific to \(dqborg create\(dq: create: compression: zstd,3 stats: true .EE .UNINDENT .UNINDENT .sp The top\-level keys set options that are common to all commands (equivalent to placing them before the subcommand on the command line). Keys nested under a subcommand name (e.g. \fBcreate:\fP) are only applied when that subcommand is invoked. .sp \fBborgfs\fP reads the same config files, but as it has no subcommands, it uses the top\-level keys and the keys of the \fBmount:\fP section (\fBborgfs\fP is the \fBborg mount\fP command, and its keys win over the top\-level ones); all other subcommand sections are ignored. .UNINDENT .sp \fBNote:\fP .INDENT 0.0 .INDENT 3.5 \fB\-\-print_config\fP shows the merged effective configuration and is a convenient way to check what values Borg will actually use, and to generate contents for your borg config file(s): .INDENT 0.0 .INDENT 3.5 .sp .EX borg \-\-repo /backup/main \-\-print_config create \-\-compression zstd,3 .EE .UNINDENT .UNINDENT .UNINDENT .UNINDENT .SS Environment Variables .\" IMPORTANT: this file is auto-generated from borg's built-in help, do not edit! . .sp Borg uses some environment variables for automation: .INDENT 0.0 .TP .B General: .INDENT 7.0 .TP .B BORG_REPO When set, use the value to give the default repository location. Use this so you do not need to type \fB\-\-repo /path/to/my/repo\fP all the time. .TP .B BORG_OTHER_REPO Similar to BORG_REPO, but gives the default for \fB\-\-other\-repo\fP\&. .TP .B BORG_PASSPHRASE (and BORG_OTHER_PASSPHRASE) When set, use the value to answer the passphrase question for encrypted repositories. It is used when a passphrase is needed to access an encrypted repo as well as when a new passphrase should be initially set when initializing an encrypted repo. BORG_PASSPHRASE, BORG_PASSCOMMAND and BORG_PASSPHRASE_FD are mutually exclusive: if more than one of them is set, borg refuses to guess and aborts with \(dqMore than one passphrase environment variable is set\(dq. The same applies to the \fBBORG_OTHER_*\fP variants (which are a separate, independent group). See also BORG_NEW_PASSPHRASE. .TP .B BORG_PASSCOMMAND (and BORG_OTHER_PASSCOMMAND) When set, use the standard output of the command (trailing newlines are stripped) to answer the passphrase question for encrypted repositories. It is used when a passphrase is needed to access an encrypted repo as well as when a new passphrase should be initially set when initializing an encrypted repo. Note that the command is executed without a shell. So variables, like \fB$HOME\fP will work, but \fB~\fP won\(aqt. Mutually exclusive with BORG_PASSPHRASE and BORG_PASSPHRASE_FD, see there. See also BORG_NEW_PASSPHRASE. .TP .B BORG_PASSPHRASE_FD (and BORG_OTHER_PASSPHRASE_FD) When set, specifies a file descriptor to read a passphrase from. Programs starting borg may choose to open an anonymous pipe and use it to pass a passphrase. This is safer than passing via BORG_PASSPHRASE, because on some systems (e.g. Linux) environment can be examined by other processes. Mutually exclusive with BORG_PASSPHRASE and BORG_PASSCOMMAND, see there. .TP .B BORG_NEW_PASSPHRASE When set, use the value to answer the passphrase question when a \fBnew\fP passphrase is asked for. This variable is checked first. If it is not set, BORG_PASSPHRASE, BORG_PASSCOMMAND and BORG_PASSPHRASE_FD are checked (in that order). Main use case for this is to fully automate \fBborg key change\-passphrase\fP\&. .TP .B BORG_DISPLAY_PASSPHRASE When set, use the value to answer the \(dqdisplay the passphrase for verification\(dq question when defining a new passphrase for encrypted repositories. .TP .B BORG_DEBUG_PASSPHRASE When set to YES, display debugging information that includes passphrases used and passphrase related env vars set. .TP .B BORG_EXIT_CODES When set to \(dqmodern\(dq, the borg process will return more specific exit codes (rc). When set to \(dqlegacy\(dq, the borg process will return rc 2 for all errors, 1 for all warnings, 0 for success. Default is \(dqmodern\(dq. .TP .B BORG_HOST_ID Borg usually computes a host id from the FQDN plus the results of \fBuuid.getnode()\fP (which usually returns a unique id based on the MAC address of the network interface. Except if that MAC happens to be all\-zero \- in that case it returns a random value, which is not what we want (because it kills automatic stale lock removal). So, if you have an all\-zero MAC address or other reasons to better control the host id externally, just set this environment variable to a unique value. If all your FQDNs are unique, you can just use the FQDN. If not, use \%\&. .TP .B BORG_HOSTNAME When set, use this value as the hostname (instead of the auto\-detected one), e.g. to run borg on one host, but impersonate another host. This affects the hostname stored in newly created archives as well as the \fB{hostname}\fP placeholder. .TP .B BORG_USERNAME When set, use this value as the username (instead of the auto\-detected one), e.g. to run borg as one user, but impersonate another user. This affects the username stored in newly created archives as well as the \fB{user}\fP placeholder. .TP .B BORG_LOCK_WAIT You can set the default value for the \fB\-\-lock\-wait\fP option with this, so you do not need to give it as a command line option. .TP .B BORG_LOGGING_CONF When set, use the given filename as INI\-style logging configuration (see \%). A basic example conf can be found at \fBdocs/misc/logging.conf\fP\&. .TP .B BORG_RSH When set, use this command instead of \fBssh\fP\&. This can be used to specify ssh options, such as a custom identity file \fBssh \-i /path/to/private/key\fP\&. See \fBman ssh\fP for other options. This is the replacement for the removed \fB\-\-rsh CMD\fP command line option. borg also gives this to borgstore as \fBBORGSTORE_RSH\fP, except if that is already set. .TP .B BORG_REMOTE_PATH When set, use the given path as borg executable on the remote (defaults to \(dqborg\(dq if unset). This is the replacement for the removed \fB\-\-remote\-path PATH\fP command line option. .TP .B BORG_UNITS Determines how borg formats sizes in its human\-readable output: .INDENT 7.0 .IP \(bu 2 \fBsi\fP (default): decimal units, e.g. \fB1.23 MB\fP (1kB = 1000B) .IP \(bu 2 \fBiec\fP: binary units, e.g. \fB1.18 MiB\fP (1KiB = 1024B) .IP \(bu 2 \fBraw\fP: exact byte counts, e.g. \fB1234567 B\fP .UNINDENT .sp Use \fBraw\fP if you want to parse sizes with scripts (e.g. for monitoring), so you do not have to deal with scaled values and different units. Alternatively, use a command\(aqs \fB\-\-json\fP output or, for the commands supporting \fB\-\-format\fP, the size related format keys \- sizes are given as byte counts there anyway. .sp \fBBORG_UNITS=iec\fP is the replacement for the removed \fBBORG_IEC\fP environment variable (and for the \fB\-\-iec\fP command line option removed before that). .TP .B BORG_PROGRESS_FPS How often the \fB\-\-progress\fP output is updated at most, in updates per second (default: 5). Fractional values are allowed, e.g. \fBBORG_PROGRESS_FPS=0.1\fP limits it to one update every 10 seconds. Lower values are useful when the output goes into a logfile rather than to an interactive terminal. .TP .B BORG_SPINNER Controls the spinner borg animates on a terminal while doing work of unknown duration: .INDENT 7.0 .IP \(bu 2 unset (default): animate, using Unicode frames if the terminal can display them .IP \(bu 2 \fBascii\fP: animate, but only use ASCII frames (\fB|/\-\e\fP) .IP \(bu 2 \fBoff\fP: do not animate, only output the messages next to the spinner .UNINDENT .sp The spinner is animated only on an interactive terminal anyway (and never with \fB\-\-log\-json\fP), and its colour follows the usual \fBNO_COLOR\fP and \fBCOLORTERM\fP conventions. See also \fBBORG_PROGRESS_FPS\fP: it also gives the spinner its frame rate. .TP .B BORG_DEBUG_PROFILE When set to a filename, write an execution profile in Borg format into that file (see \fIdebugging\fP). If the filename ends with \fB\&.pyprof\fP, a Python\-compatible profile is written instead. This is the replacement for the removed \fB\-\-debug\-profile\fP command line option. Note: every borg invocation writes the profile, so unset it again when you are done. .TP .B BORG_REPO_PERMISSIONS Set repository permissions, see also: \fIborg_serve\fP .TP .B BORG_FILES_CACHE_SUFFIX When set to a value at least one character long, instructs borg to use a specifically named (based on the suffix) alternative files cache. This can be used to avoid loading and saving cache entries for backup sources other than the current sources. .TP .B BORG_FILES_CACHE_TTL When set to a numeric value, this determines the maximum \(dqtime to live\(dq for the files cache entries (default: 2). The files cache is used to determine quickly whether a file is unchanged. .TP .B BORG_STORE_CACHE When set, borg keeps a local writethrough cache of the repository\(aqs \fBpacks/\fP namespace: on a cache miss the whole pack is fetched once and later reads of the objects inside that pack are served from the cache. Use this for slow or high\-latency repositories. Set it to \fB1\fP to use \fB$BORG_CACHE_DIR/storecache\fP, or to a directory path to use that directory (it is created if it does not exist). Packs are named by content hash, so one cache directory can safely hold packs of multiple repositories. If it is not set, no such caching happens. .TP .B BORG_PACK_CACHE_SIZE When set to a numeric value, limit the pack cache to that many bytes. Only has an effect if BORG_STORE_CACHE is set. .TP .B BORG_PACK_MAX_SIZE When set to a numeric value, cap packs (the repository objects that batch up many chunks, see the internals documentation about pack files) at that many bytes instead of the default of 50000000. Smaller packs mean more (but smaller) repository objects and more fine\-grained uploads; bigger packs mean fewer objects and fewer stores. .TP .B BORG_PACK_MAX_COUNT When set to a numeric value, cap packs at that many objects per pack. If BORG_PACK_MAX_SIZE is not also set, packs are then bound by count only. .TP .B BORG_PACK_ASYNC When set to \fBno\fP, disable the background thread that stores a finished pack while the next one is being assembled, and store packs synchronously instead. This is mainly a debugging aid. .TP .B BORG_PACK_TRACE When set to \fByes\fP, print one\-character lifecycle markers of the background pack store\-thread to stderr (\fB<\fP thread started, \fBH\fP hashing starts, \fBS\fP storing starts, \fB>\fP thread finished). This is a debugging aid to visualize how pack stores overlap with the assembly of the next pack. .TP .B BORG_ASSERT_ID Comma\-separated list of the places where borg shall verify that a chunk\(aqs content matches its chunk id (\fBchunkid == id_hash(content)\fP) after decrypting and decompressing it. Verifying costs a full hash pass over everything that is read at such a place. .sp Default (variable not set): .INDENT 7.0 .INDENT 3.5 .sp .EX BORG_ASSERT_ID=repair,transfer,rechunk .EE .UNINDENT .UNINDENT .sp These are the place names that can be listed: .INDENT 7.0 .TP .B read Every read that decompresses a chunk: \fBborg extract\fP, \fBborg mount\fP, \fBborg export\-tar\fP, \fBborg diff\fP, ... This is by far the most data borg reads, so this place is \fBnot\fP in the default, see the explanation below. .TP .B repair \fBborg check \-\-repair\fP\&. It rebuilds archives from the item metadata stream it reads, re\-packing it into new chunks with freshly computed ids, and it recreates manifest and archives directory entries from what it reads. .TP .B transfer \fBborg transfer\fP, for everything it reads from the source repository. Transferring re\-anchors the content in another repository, which is a trust boundary. .TP .B rechunk \fBborg recreate \-\-chunker\-params ...\fP, i.e. re\-chunking reads. Re\-chunking computes new chunk ids from the content it reads, so a violation would not be noticeable any more afterwards. (Re\-chunking in \fBborg transfer\fP is covered by \fBtransfer\fP\&.) .UNINDENT .sp An unknown place name is an error. An empty value (\fBBORG_ASSERT_ID=\fP) verifies at none of these places, but still where borg always verifies (see below). .sp Why \fBread\fP is not in the default: in the keyed modes, the envelope already authenticates every read \- the AEAD tag for the encrypted ciphersuites, the MAC for the (unencrypted) \fBauthenticated\-*\fP modes \- and the chunk id is part of what that tag is computed over. So a successful decryption resp. tag check already proves that a holder of the borg key deliberately stored exactly this payload for exactly this chunk id, and a malicious or buggy \fBrepository\fP can not swap, splice or substitute objects, whether the id is verified on read or not. What the id check adds is the detection of chunks whose content does not match their id, which only a malicious or compromised \fBborg client that had your borg key\fP could have written (e.g. to poison future deduplication). If that is in your threat model \- e.g. because some machines writing into the repository are not fully trusted \- add \fBread\fP to the list: .INDENT 7.0 .INDENT 3.5 .sp .EX BORG_ASSERT_ID=read,repair,transfer,rechunk .EE .UNINDENT .UNINDENT .sp Otherwise, running \fBborg check \-\-verify\-data\fP periodically is recommended: it is the audit that re\-certifies the invariant for all chunks in the background, instead of on every read. .sp Independent of this variable, borg always verifies the chunk id: .INDENT 7.0 .IP \(bu 2 in \fBborg check \-\-verify\-data\fP\&. That audit is what makes not verifying elsewhere defensible, so it is not configurable (there is no \fBverify_data\fP place name). .IP \(bu 2 for \fBnone\-*\fP mode repositories: they have no key, so nothing authenticates a read there and their unkeyed checksums only detect accidental corruption. The id check is therefore not optional there: it happens at every place, whatever this variable says. Same for reading borg 1.x repositories (\fBborg transfer\fP). .UNINDENT .TP .B BORG_BLAKE3_MT_THRESHOLD When set to a numeric value, chunks of at least that many KiB get their id computed by multi\-threaded BLAKE3, smaller ones single\-threaded (default: 256, i.e. 256KiB). Only relevant for repositories using \fB\-\-id\-hash blake3\fP\&. Multi\-threading only pays off for big enough chunks and the break\-even point depends on the machine\(aqs core count, so the default is deliberately conservative. Run \fBscripts/blake3\-optimize\-mt\-threshold.py\fP to measure the best value for your machine \- it sweeps input sizes, prints the recommended threshold and the command to set it, and can optionally show a chart of the measurements in your browser (\fB\-\-html \-\-open\fP). 0 means \(dqalways multi\-threaded\(dq, a very large value effectively disables multi\-threading. .TP .B BORG_ZSTD_MT_WORKERS When set to a numeric value, use that many threads to zstd\-compress a single chunk (default: the cpu count, but at most 4). 0 or 1 means single\-threaded compression. Only relevant when compressing with \fBzstd\fP\&. Chunks below 768KiB are always compressed single\-threaded: libzstd will not use a compression job smaller than 512KiB, so a small chunk gets split very unevenly and multi\-threading it would be slower than not doing it at all. The default is capped at 4 because a chunk of the size the default chunker aims at (2MiB) splits into just 4 such jobs: threads beyond that get (nearly) no work, but the whole thread pool is created again for every chunk. Measured on a 12\-core machine, 4 threads beat 12 on every test corpus at the default \fBzstd,\-4\fP (+13% .. +37%). Raising the value only pays off if you configured the chunker for much bigger chunks. \fBborg export\-tar\fP compresses one long stream instead of separate chunks and always defaults to the cpu count. Multi\-threading trades a little compression ratio for speed (measured at \fBzstd,3\fP: +0.05% archive size for 1MiB chunks, +0.64% for 8MiB ones, more at higher levels), and it uses more cpu time in total to reduce the wallclock time. Set it to 1 if you would rather have the smaller archive, or if borg has to share the cpu with other work. Single\-threaded can even be faster on data zstd races through anyway, e.g. already\-compressed/incompressible data or long\-repeat data like VM images. .TP .B BORG_FASTCDC_KERNEL / BORG_BUZHASH64_KERNEL Select the scan kernel the \fBfastcdc\fP / \fBbuzhash64\fP chunker uses. Accepted values are \fBavx512\fP, \fBavx2\fP, \fBneon\fP, \fBblockwise\fP and \fBscalar\fP\&. The default is whichever benchmarked fastest for the architecture: \fBneon\fP on aarch64, and \fBscalar\fP (the plain sequential loop) on x86\-64, where the compiler folds the rolling hash update into a single instruction and thereby beats the vector kernels. Other architectures get \fBblockwise\fP, the portable multi\-lane C kernel. All kernels chunk identically \- same cut points, same chunk ids \- and differ only in speed, so this is safe to change at any time, also for an existing repository. Which kernel is fastest is not predictable from the instruction set: it depends on the cpu and on the compiler that built borg, and the sequential loop wins on some machines. Measure on your own hardware with \fBborg benchmark cpu \-\-chunking\fP before overriding the default. \fBavx512\fP and \fBavx2\fP exist only on x86\-64, \fBneon\fP only on aarch64, and only if the compiler that built borg supported them; \fBscalar\fP and \fBblockwise\fP are portable C and always available. Requesting a kernel that this build or this cpu cannot run is an error rather than a silent fallback, so a benchmark can not accidentally measure a different kernel. \fBborg create \-\-debug\fP logs the chunker and the kernel it was created with. .TP .B BORG_AES_CHUNKER_KERNEL Select the scan kernel used by the AES based chunkers \- one variable for all three of \fBtoeplitz\-aes\fP, \fBrabin\-aes\fP and \fBgoldilocks\-aes\fP\&. Accepted values are \fBvaes\fP, \fBaes\-ni\fP, \fBaes\-arm64\fP and \fBevp\fP\&. Unlike the chunker kernels above, wider is simply faster here, so the default is the best path this build and cpu offer: \fBvaes\fP, else \fBaes\-ni\fP on x86\-64, \fBaes\-arm64\fP on aarch64, and \fBevp\fP (the portable OpenSSL path) where there is no AES hardware path. As with the chunker kernels above, all of them chunk identically and differ only in speed, and a kernel that can not run here is an error rather than a silent fallback. \fBvaes\fP and \fBaes\-ni\fP exist only on x86\-64, \fBaes\-arm64\fP only on aarch64. \fBvaes\fP additionally needs a compiler that knows it (gcc >= 11 / clang >= 14), so a cpu supporting VAES is not by itself enough to have that kernel available. .TP .B BORG_SHOW_SYSINFO When set to no (default: yes), system information (like OS, Python version, ...) in exceptions is not shown. Please only use for good reasons as it makes issues harder to analyze. .TP .B BORG_MSGPACK_VERSION_CHECK Controls whether Borg checks the \fBmsgpack\fP version. The default is \fByes\fP (strict check). Set to \fBno\fP to disable the version check and allow any installed \fBmsgpack\fP version. Use this at your own risk; malfunctioning or incompatible \fBmsgpack\fP versions may cause subtle bugs or repository data corruption. .TP .B BORG_FUSE_IMPL Choose the low\-level FUSE implementation borg shall use for \fBborg mount\fP\&. This is a comma\-separated list of implementation names, they are tried in the given order, e.g.: .INDENT 7.0 .IP \(bu 2 \fBmfusepy,pyfuse3,llfuse\fP: default, first try to load mfusepy, then pyfuse3, then llfuse. .IP \(bu 2 \fBllfuse,pyfuse3\fP: first try to load llfuse, then try to load pyfuse3. .IP \(bu 2 \fBmfusepy\fP: only try to load mfusepy .IP \(bu 2 \fBpyfuse3\fP: only try to load pyfuse3 .IP \(bu 2 \fBllfuse\fP: only try to load llfuse .IP \(bu 2 \fBnone\fP: do not try to load an implementation .UNINDENT .TP .B BORG_MOUNT_DATA_CACHE_ENTRIES Number of decrypted file content chunks \fBborg mount\fP and \fBborg webdav\fP keep in an in\-memory cache, so that the many small, sequential reads a mounted file system does for a big file do not re\-fetch and re\-decrypt the same chunk over and over (default: the cpu count). Additional memory usage can be up to the chunk size times this number. .TP .B BORG_SELFTEST This can be used to influence borg\(aqs built\-in self\-tests. The default is to execute the tests at the beginning of each borg command invocation. .sp BORG_SELFTEST=disabled can be used to switch off the tests and rather save some time. Disabling is not recommended for normal borg users, but large scale borg storage providers can use this to optimize production servers after at least doing a one\-time test borg (with self\-tests not disabled) when installing or upgrading machines/OS/Borg. .TP .B BORG_WORKAROUNDS A list of comma\-separated strings that trigger workarounds in borg, e.g. to work around bugs in other software. .sp Currently known strings are: .INDENT 7.0 .TP .B basesyncfile Use the more simple BaseSyncFile code to avoid issues with sync_file_range. You might need this to run borg on WSL (Windows Subsystem for Linux) or in systemd.nspawn containers on some architectures (e.g. ARM). Using this does not affect data safety, but might result in a more bursty write\-to\-disk behavior (not continuously streaming to disk). .TP .B retry_erofs Retry opening a file without O_NOATIME if opening a file with O_NOATIME caused EROFS. You will need this to make archives from volume shadow copies in WSL1 (Windows Subsystem for Linux 1). .TP .B authenticated_no_key Work around a lost passphrase or a lost borg key for an \fBauthenticated\-*\fP mode repository (these are only authenticated, but not encrypted). If a borg key is found \- an object below \fBkeys/\fP in the repository (repokey) resp. a key file in the keys directory (keyfile) \- it is not unlocked, so the passphrase does not matter. If no borg key is found at all, borg proceeds anyway, without any key material. .sp Without the key, borg can not verify anything that needs it: neither the authentication tag of the repository objects nor the chunk ids. It therefore reads the repository \fBunverified\fP \- a corrupted or tampered repository will not be detected. (This only concerns the \fBauthenticated\-*\fP modes; the \fBnone\-*\fP modes need no key and keep verifying their checksums.) .sp This workaround is \fBonly\fP for emergencies and \fBonly\fP to extract data from an affected repository (read\-only access): .INDENT 7.0 .INDENT 3.5 .sp .EX BORG_WORKAROUNDS=authenticated_no_key borg extract \-\-repo repo archive .EE .UNINDENT .UNINDENT .sp After you have extracted all data you need, you MUST delete the repository: .INDENT 7.0 .INDENT 3.5 .sp .EX BORG_WORKAROUNDS=authenticated_no_key borg repo\-delete \-\-repo repo .EE .UNINDENT .UNINDENT .sp Now you can create a fresh repository with \fBborg repo\-create\fP\&. Make sure you do not use the workaround any more. .UNINDENT .UNINDENT .TP .B Output formatting: .INDENT 7.0 .TP .B BORG_CHECK_FORMAT Giving the default value for \fBborg check \-\-format=X\fP\&. .TP .B BORG_DIFF_FORMAT Giving the default value for \fBborg diff \-\-format=X\fP\&. Note: \fBborg diff \-\-content\-only\fP uses its own format and ignores this. .TP .B BORG_FIND_FORMAT Giving the default value for \fBborg find \-\-format=X\fP\&. .TP .B BORG_LIST_FORMAT Giving the default value for \fBborg list \-\-format=X\fP\&. .TP .B BORG_REPO_LIST_FORMAT Giving the default value for \fBborg repo\-list \-\-format=X\fP\&. .TP .B BORG_PRUNE_FORMAT Giving the default value for \fBborg prune \-\-format=X\fP\&. .TP .B BORG_MOUNT_ARCHIVE_DIR_FORMAT Giving the format of the archive directory names when \fBborg mount\fP or \fBborg webdav\fP show a whole repository, default: \fB{name}\fP\&. The placeholders are the ones of \fBborg repo\-list \-\-format\fP; names that are not unique get \fB\-{id:.8}\fP appended. See \fBborg mount \-\-help\fP\&. .TP .B BORG_JSON_INDENT Indentation of the \fB\-\-json\fP output (default: \fB4\fP). A number gives that many spaces per nesting level (\fB0\fP still puts every item on its own line), \fBnone\fP gives compact single\-line JSON, and any other value is used as the literal indent string (e.g. a tab or the empty string). .UNINDENT .TP .B Some automatic \(dqanswerers\(dq (if set, they automatically answer confirmation questions): .INDENT 7.0 .TP .B BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=no (or =yes) For \(dqWarning: Attempting to access a previously unknown unencrypted repository\(dq .TP .B BORG_RELOCATED_REPO_ACCESS_IS_OK=no (or =yes) For \(dqWarning: The repository at location ... was previously located at ...\(dq .TP .B BORG_CHECK_I_KNOW_WHAT_I_AM_DOING=NO (or =YES) For \(dqThis is a potentially dangerous function...\(dq (check \-\-repair) .TP .B BORG_DELETE_I_KNOW_WHAT_I_AM_DOING=NO (or =YES) For \(dqYou requested to DELETE the repository completely \fIincluding\fP all archives it contains:\(dq .UNINDENT .sp Note: answers are case sensitive. setting an invalid answer value might either give the default answer or ask you interactively, depending on whether retries are allowed (they by default are allowed). So please test your scripts interactively before making them a non\-interactive script. .TP .B Directories and files: Borg 2 uses the platformdirs library (\%) to determine default directory locations. This means that default paths are \fBplatform\-specific\fP: .INDENT 7.0 .IP \(bu 2 Linux: XDG Base Directory Specification paths are used (e.g. \fB~/.config/borg\fP, \fB~/.cache/borg\fP, \fB~/.local/share/borg\fP). \fBXDG_*\fP environment variables are honoured (see \%). .IP \(bu 2 macOS: native macOS directories are used by default (e.g. \fB~/Library/Application Support/borg\fP, \fB~/Library/Caches/borg\fP). \fBXDG_*\fP environment variables are honoured if set. .IP \(bu 2 Windows: local (not roaming) Windows AppData directories are used, e.g. \fBC:\eUsers\e\eAppData\eLocal\eborg\eborg\fP\&. \fBborg\fP appears twice in that path because borg does not give platformdirs a separate \(dqapp author\(dq name, so it defaults to the app name. \fBXDG_*\fP environment variables are \fBnot\fP honoured. .UNINDENT .sp On all platforms, you can override each directory individually using the specific environment variables described below. You can also set \fBBORG_BASE_DIR\fP to force borg to use \fBBORG_BASE_DIR/.config/borg\fP, \fBBORG_BASE_DIR/.cache/borg\fP, etc., regardless of the platform. .sp Default directory locations by platform (when no \fBBORG_*\fP environment variables are set): .INDENT 7.0 .INDENT 3.5 .sp .EX Directory Linux macOS Windows Config ~/.config/borg ~/Library/Application Support/borg %LOCALAPPDATA%\eborg\eborg Cache ~/.cache/borg ~/Library/Caches/borg %LOCALAPPDATA%\eborg\eborg\eCache Data ~/.local/share/borg ~/Library/Application Support/borg %LOCALAPPDATA%\eborg\eborg Runtime /run/user//borg ~/Library/Caches/TemporaryItems/borg %LOCALAPPDATA%\eTemp\eborg\eborg Keys /keys /keys \ekeys Security /security /security \esecurity .EE .UNINDENT .UNINDENT .INDENT 7.0 .TP .B BORG_BASE_DIR Not set by default \- then the platform\-specific directories shown in the table above are used. If you want to move all borg\-specific folders to a custom path at once, all you need to do is to modify \fBBORG_BASE_DIR\fP: the other paths for cache, config etc. will adapt accordingly (assuming you didn\(aqt set them to a different custom value). .TP .B BORG_CACHE_DIR Defaults to the platform\-specific cache directory (see table above). If \fBBORG_BASE_DIR\fP is set, defaults to \fB$BORG_BASE_DIR/.cache/borg\fP\&. On Linux and macOS, \fBXDG_CACHE_HOME\fP is also honoured if \fBBORG_BASE_DIR\fP is not set. This directory contains the local cache and might need a lot of space for dealing with big repositories. Make sure you\(aqre aware of the associated security aspects of the cache location: \fIcache_security\fP .TP .B BORG_CONFIG_DIR Defaults to the platform\-specific config directory (see table above). If \fBBORG_BASE_DIR\fP is set, defaults to \fB$BORG_BASE_DIR/.config/borg\fP\&. On Linux and macOS, \fBXDG_CONFIG_HOME\fP is also honoured if \fBBORG_BASE_DIR\fP is not set. This directory contains all borg configuration directories, see the FAQ for a security advisory about the data in this directory: \fIhome_config_borg\fP .TP .B BORG_DATA_DIR Defaults to the platform\-specific data directory (see table above). If \fBBORG_BASE_DIR\fP is set, defaults to \fB$BORG_BASE_DIR/.local/share/borg\fP\&. On Linux and macOS, \fBXDG_DATA_HOME\fP is also honoured if \fBBORG_BASE_DIR\fP is not set. This directory contains all borg data directories, see the FAQ for a security advisory about the data in this directory: \fIhome_data_borg\fP .TP .B BORG_RUNTIME_DIR Defaults to the platform\-specific runtime directory (see table above). If \fBBORG_BASE_DIR\fP is set, defaults to \fB$BORG_BASE_DIR/.cache/borg\fP\&. On Linux and macOS, \fBXDG_RUNTIME_DIR\fP is also honoured if \fBBORG_BASE_DIR\fP is not set. This directory contains borg runtime files, like e.g. the socket file. .TP .B BORG_SECURITY_DIR Defaults to \fB$BORG_DATA_DIR/security\fP\&. This directory contains security relevant data. .TP .B BORG_KEYS_DIR Defaults to \fB$BORG_CONFIG_DIR/keys\fP\&. This directory contains keys for encrypted repositories. .TP .B BORG_KEY_FILE When set, use the given path as repository key file. Please note that this is only for rather special applications that externally fully manage the key files: .INDENT 7.0 .IP \(bu 2 this setting only applies to the keyfile modes (not to the repokey modes). .IP \(bu 2 using a full, absolute path to the key file is recommended. .IP \(bu 2 all directories in the given path must exist. .IP \(bu 2 this setting forces borg to use the key file at the given location. .IP \(bu 2 the key file must either exist (for most commands) or will be created (\fBborg repo\-create\fP). .IP \(bu 2 you need to give a different path for different repositories. .IP \(bu 2 you need to point to the correct key file matching the repository the command will operate on. .UNINDENT .TP .B TMPDIR This is where temporary files are stored (might need a lot of temporary space for some operations), see \% for details. .UNINDENT .TP .B Building: These are only read by \fBsetup.py\fP while building borg\(aqs C extensions. Each \fBBORG_*_PREFIX\fP variable names the install prefix of a library that borg links against: if it is set, \fB$PREFIX/include\fP and \fB$PREFIX/lib\fP are used unconditionally. If it is not set, the library is located via pkg\-config, and if that does not find it either, the build fails \- there is no bundled fallback implementation. .INDENT 7.0 .TP .B BORG_OPENSSL_PREFIX Prefix of the OpenSSL installation to build libcrypto against. On Windows, the libraries are expected in \fB$PREFIX\fP itself rather than in \fB$PREFIX/lib\fP\&. On OpenBSD, this defaults to \fB/usr/local\fP, pkg\-config is not used and libcrypto is linked statically (borg needs AES\-OCB via the EVP API, which LibreSSL does not have). .TP .B BORG_OPENSSL_NAME OpenBSD only: the OpenSSL flavour to use, i.e. the \fBinclude/\fP and \fBlib/\fP subdirectory name below \fBBORG_OPENSSL_PREFIX\fP (default: \fBeopenssl35\fP). .TP .B BORG_LIBLZ4_PREFIX Prefix of the liblz4 installation to build against. .TP .B BORG_LIBACL_PREFIX Linux only: prefix of the libacl installation to build against. .UNINDENT .TP .B Automatic option environment variables: Borg uses jsonargparse (\%) with \fBdefault_env=True\fP, which means that every command\-line option can also be set via an environment variable. .sp The environment variable name is derived from the program name (\fBborg\fP), the subcommand (if any), and the option name, all converted to uppercase with dashes replaced by underscores. .sp For \fBtop\-level options\fP (not specific to a subcommand), the pattern is: .INDENT 7.0 .INDENT 3.5 .sp .EX BORG_