How to run a command on all ZFS snapshot outputs in FreeBSD?

mike_plumbs

When I boot into single-user mode and list the ZFS snapshots I'm interested in, I want to revert to the "xfcedesktop" snapshot. However, this requires me to manually type the command zfs rollback snapshotname@xfcedesktop for each snapshot, like this: # zfs list -t snapshot -o name | grep xfcedesktop zroot@xfcedesktop zroot/ROOT@xfcedesktop zroot/ROOT/default@xfcedesktop zroot/home@xfcedesktop zroot/home/zoliky@xfcedesktop zroot/tmp@xfcedesktop...

Originally asked by Zoltan King on Stack Exchange (unix) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

Use either a simple while loop, as in zfs list -H -t snapshot -o name | grep '@xfcedesktop$' | while IFS= read -r snapshot; do zfs rollback "$snapshot" done ... or use xargs zfs list -H -t snapshot -o name | grep '@xfcedesktop$' | xargs -r -I {} zfs rollback {} The -r option to xargs is supported but unnecessary on FreeBSD. With GNU's xargs , the option prevents the utility from trying to run the utility if the input is empty. This is the default behaviour of FreeBSD's xargs . I've also been more careful with the regular expression used with grep to ensure we only get the expected snapshots (the ones ending in exactly @xfcedesktop ).

Full answer by Kusalananda: https://unix.stackexchange.com/a/791615 (CC BY-SA 4.0).

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