borg/docs/man/borg-prune.1

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.TH "borg-prune" "1" "2026-08-29" "" "borg backup tool"
.SH Name
borg-prune \- Prune archives according to specified rules.
.SH SYNOPSIS
.sp
borg [common options] prune [options] [NAME]
.SH DESCRIPTION
.sp
The prune command prunes a repository by soft\-deleting all archives not
matching any of the specified retention options.
.sp
Important:
.INDENT 0.0
.IP \(bu 2
The prune command will only mark archives for deletion (\(dqsoft\-deletion\(dq),
repository disk space is \fBnot\fP freed until you run \fBborg compact\fP\&.
.IP \(bu 2
You can use \fBborg undelete\fP to undelete archives, but only until
you run \fBborg compact\fP\&.
.UNINDENT
.sp
This command is normally used by automated backup scripts wanting to keep a
certain number of historic backups. This retention policy is commonly referred to as
GFS \%<https://\:en\:.wikipedia\:.org/\:wiki/\:Backup_rotation_scheme#\:Grandfather-father-son>
(Grandfather\-father\-son) backup rotation scheme.
.sp
The recommended way to use prune is to give the archive series name to it via the
NAME argument (assuming you have the same name for all archives in a series).
Alternatively, you can also use \-\-match\-archives (\-a), then only archives that
match the pattern are considered for deletion and only those archives count
towards the totals specified by the rules.
Otherwise, \fIall\fP archives in the repository are candidates for deletion!
There is no automatic distinction between archives representing different
contents. These need to be distinguished by specifying matching globs.
.sp
If you have multiple series of archives with different data sets (e.g.
from different machines) in one shared repository, use one prune call per
series.
.sp
The \fB\-\-keep\fP option is the simplest way to specify a basic retention
policy. It accepts a count or a time interval for retention (e.g.
\fB10\fP or \fB7d\fP, \fB4w\fP). With a count it keeps at most that many
recent archives; with an interval it keeps all archives created within
that time window. When \fB\-\-from\fP is given together with an interval
retention, the interval is measured backwards from that timestamp
instead of from the current time. See \fBDate and Time\fP docs for exact
INTERVAL format.
.sp
The \fB\-\-keep\-secondly\fP, \fB\-\-keep\-minutely\fP, \fB\-\-keep\-hourly\fP,
\fB\-\-keep\-daily\fP, \fB\-\-keep\-weekly\fP, \fB\-\-keep\-monthly\fP,
\fB\-\-keep\-13weekly\fP, \fB\-\-keep\-3monthly\fP, and \fB\-\-keep\-yearly\fP options
specify time period retention policies. They accept either a count N for
retention or a time interval INTERVAL for retention, same as for \fB\-\-keep\fP\&.
With a retention count, they keep at most that many archives (one per
period, e.g. one per day or one per month until the retention count is
met). With a retention interval, they keep one archive per period
within that time span (e.g. at most one per day in a span of seven
days, even if some days had none) \-\- measured from \fB\-\-from\fP if given,
otherwise from the current time. Specifying a count of \fB\-1\fP (or the
word \fBall\fP) means no limit. A zero count or zero\-length interval
keeps nothing.
.sp
The \fB\-\-from\fP option restricts pruning to archives older than the given
TIMESTAMP. Archives made at or after this timestamp are kept unconditionally
as a pre\-filter. When \fB\-\-from\fP is used together with interval\-based
\fB\-\-keep\-*\fP options (e.g. \fB\-\-keep\-daily 7d\fP), the interval is measured
backwards from the given timestamp rather than from the current time.
Count\-based retention does not count the unconditionally kept archives.
.sp
The \fB\-\-keep\-13weekly\fP and \fB\-\-keep\-3monthly\fP rules are two different
strategies for keeping archives every quarter year.
.sp
The oldest archive is kept as long as the coarsest retention rule covers it \-\-
\fB\-\-keep\-yearly=3\fP will keep the oldest archive if it couldn\(aqt otherwise find
three candidates, \fB\-\-keep\-yearly=5y\fP will keep the oldest archive as long as
it is at or within the 5y interval. This is useful for rolling tiered backup
schemes, where the earliest backup in a retention window should survive until
the next tier\(aqs interval naturally replaces it.
.sp
When using interval\-based pruning with multiple \fB\-\-keep\-*\fP options,
the intervals must be specified in increasing length matching the
periods chosen. For example, \fB\-\-keep\-daily 7d \-\-keep\-weekly 4w\fP is
valid, but \fB\-\-keep\-daily 30d \-\-keep\-weekly 7d\fP is not, because the
weekly interval is already covered by the daily one and so the weekly
interval is effectively useless. An error is emitted upon running
\fBborg prune\fP if such a combination of flags is given. The order of
flags on the command line is not significant.
.sp
A practical approach for recurring backups is to use rules
with increasing coarseness so that most of recent history is kept and
older history gradually thins out with time. For example,
\fB\-\-keep\-daily 7d \-\-keep\-weekly 4w \-\-keep\-monthly 6\fP keeps an
archive per day for the past week, per week for the past month, and
one per month for six months after that. Combine this with \fB\-\-from\fP
to align time windows to calendar boundaries rather than the exact
moment you run prune for more predictable behavior of coarser rules:
\fB\-\-keep\-daily 7d \-\-keep\-weekly 4w \-\-from $(date +%F)\fP\&.
.sp
Count\-based retention keeps archives less bound to time. For instance,
\fB\-\-keep\-yearly 3\fP retains 3 yearly archives however far back they
span and \fB\-\-keep\-daily 20\fP keeps 20 archives no matter if you missed
a week in between. This can be useful for less regular archive
creation, or if your use case does not map well to specific time
intervals, or if you simply prefer to think of archive retention in
numbers rather than intervals.
.sp
For count\-based retention, backups selected by more granular rules do
not count towards those of coarser rules. \fB\-\-keep 3 \-\-keep\-monthly 2\fP
will first keep the 3 latest archives and then keep 2 monthly archives,
skipping ones that were already kept by \fB\-\-keep 3\fP\&.
.sp
The time that each archive creation started is used to match archives
to pruning periods. Dates and times are interpreted in the local
timezone of your system. Weeks go from Monday to Sunday.
.sp
You can influence how the \fB\-\-list\fP output is formatted by using the \fB\-\-short\fP
option (less wide output) or by giving a custom format using \fB\-\-format\fP (see
the \fBborg repo\-list\fP description for more details about the format string).
.SH OPTIONS
.sp
See \fIborg\-common(1)\fP for common options of Borg commands.
.SS arguments
.INDENT 0.0
.TP
.B NAME
specify the archive name
.UNINDENT
.SS options
.INDENT 0.0
.TP
.B  \-n\fP,\fB  \-\-dry\-run
do not change the repository
.TP
.B  \-\-list
output a verbose list of archives it keeps/prunes
.TP
.B  \-\-short
use a less wide archive part format
.TP
.B  \-\-list\-pruned
output verbose list of archives it prunes
.TP
.B  \-\-list\-kept
output verbose list of archives it keeps
.TP
.BI \-\-format \ FORMAT
specify format for the archive part (default: \(dq{archive:<36} {time} [{id}]\(dq)
.TP
.B  \-\-json
Format output as JSON. The form of \fB\-\-format\fP is ignored, but keys used in it are added to the JSON output. Some keys are always present. Note: JSON can only represent text.
.TP
.BI \-\-from \ TIMESTAMP
only consider archives older than this for pruning
.TP
.B  \-\-keep
number or time interval of archives to keep
.TP
.B  \-\-keep\-secondly
number or time interval of secondly archives to keep
.TP
.B  \-\-keep\-minutely
number or time interval of minutely archives to keep
.TP
.B  \-H\fP,\fB  \-\-keep\-hourly
number or time interval of hourly archives to keep
.TP
.B  \-d\fP,\fB  \-\-keep\-daily
number or time interval of daily archives to keep
.TP
.B  \-w\fP,\fB  \-\-keep\-weekly
number or time interval of weekly archives to keep
.TP
.B  \-m\fP,\fB  \-\-keep\-monthly
number or time interval of monthly archives to keep
.TP
.B  \-\-keep\-13weekly
number or time interval of quarterly archives to keep (13 week strategy)
.TP
.B  \-\-keep\-3monthly
number or time interval of quarterly archives to keep (3 month strategy)
.TP
.B  \-y\fP,\fB  \-\-keep\-yearly
number or time interval of yearly archives to keep
.UNINDENT
.SS Archive filters
.INDENT 0.0
.TP
.BI \-a \ PATTERN\fR,\fB \ \-\-match\-archives \ PATTERN
only consider archives matching all patterns. See \(dqborg help match\-archives\(dq.
.UNINDENT
.SH EXAMPLES
.sp
Be careful: prune is a potentially dangerous command that removes backup
archives.
.sp
By default, prune applies to \fBall archives in the repository\fP unless you
restrict its operation to a subset of the archives.
.sp
The recommended way to name archives (with \fBborg create\fP) is to use the
identical archive name within a series of archives. Then you can simply give
that name to prune as well, so it operates only on that series of archives.
.sp
Alternatively, you can use \fB\-a\fP/\fB\-\-match\-archives\fP to match archive names
and select a subset of them.
When using \fB\-a\fP, be careful to choose a good pattern — for example, do not use a
prefix \(dqfoo\(dq if you do not also want to match \(dqfoobar\(dq.
.sp
It is strongly recommended to always run \fBprune \-v \-\-list \-\-dry\-run ...\fP
first, so you will see what it would do without it actually doing anything.
.sp
Do not forget to run \fBborg compact \-v\fP after prune to actually free disk space.
.sp
The \fB\-\-keep\-*\fP options accept either a \fBcount\fP (e.g. \fB\-\-keep\-daily 7\fP) or
a \fBtime interval\fP (e.g. \fB\-\-keep\-daily 7d\fP). A count keeps up to \fIN\fP archives
per period (e.g. the last 7 daily archives), while an interval keeps one
archive per period within that time span (e.g. one daily archive per day in the
last 7\-day window). When using intervals, you may also specify \fB\-\-from\fP to
set the reference timestamp for interval calculation.
.INDENT 0.0
.INDENT 3.5
.sp
.EX
# Keep 7 end of day and 4 additional end of week archives.
# Do a dry\-run without actually deleting anything.
$ borg prune \-v \-\-list \-\-dry\-run \-\-keep\-daily=7 \-\-keep\-weekly=4

# Similar to the above, but only apply to the archive series named \(aq{hostname}\(aq:
$ borg prune \-v \-\-list \-\-keep\-daily=7 \-\-keep\-weekly=4 \(aq{hostname}\(aq

# Similar to the above, but apply to archive names starting with the hostname
# of the machine followed by a \(aq\-\(aq character:
$ borg prune \-v \-\-list \-\-keep\-daily=7 \-\-keep\-weekly=4 \-a \(aqsh:{hostname}\-*\(aq

# Keep 7 end of day, 4 additional end of week archives,
# and an end of month archive for every month:
$ borg prune \-v \-\-list \-\-keep\-daily=7 \-\-keep\-weekly=4 \-\-keep\-monthly=\-1

# Keep all backups in the last 10 days, 4 additional end of week archives,
# and an end of month archive for every month:
$ borg prune \-v \-\-list \-\-keep=10d \-\-keep\-weekly=4 \-\-keep\-monthly=\-1

# Keep daily archives from the last 7 days:
$ borg prune \-v \-\-list \-\-dry\-run \-\-keep\-daily=7d

# Same as above, but with a fixed reference timestamp:
$ borg prune \-v \-\-list \-\-dry\-run \-\-from 2025\-12\-01T00:00:00+02:00 \-\-keep\-daily=7d

# Keep the last 14 archives using \(ga\-\-keep\(ga:
$ borg prune \-v \-\-list \-\-dry\-run \-\-keep 14

# Keep all archives from the last 30 days using \(ga\-\-keep\(ga:
$ borg prune \-v \-\-list \-\-dry\-run \-\-keep 30d
.EE
.UNINDENT
.UNINDENT
.sp
There are also visualized prune examples in \fBdocs/misc/prune\-example.txt\fP and
\fBdocs/misc/prune\-example\-interval.txt\fP:
.SH SEE ALSO
.sp
\fIborg\-common(1)\fP, \fIborg\-compact(1)\fP
.SH Author
The Borg Collective
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