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finalturismo
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Joined: 06 Jan 2020
Posts: 410
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 Posted: Sat Oct 15, 2022 5:01 pm Post subject: Set multiple variables from output of 1 command? |
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Ok so lets say i want to set multiple variables from the output of 1 command without running the command multiple times to set the variables.....
How would i go about doing this?
For example i want to create a variable based on each stat from the output of zfs get all rpool
| Code: | NAME PROPERTY VALUE SOURCE
rpool type filesystem -
rpool creation Sat Jun 11 20:36 2022 -
rpool used 1.27T -
rpool available 620G -
rpool referenced 316G -
rpool compressratio 1.16x -
rpool mounted yes -
rpool quota none default
rpool reservation 20G local
rpool recordsize 16K local
rpool mountpoint / local
rpool sharenfs off local
rpool checksum edonr local
rpool compression lz4 local
rpool atime on local
rpool devices on default
rpool exec on default
rpool setuid on default
rpool readonly off default
rpool zoned off default
rpool snapdir hidden default
rpool aclmode passthrough local
rpool aclinherit passthrough local
rpool createtxg 1 -
rpool canmount on local
rpool xattr sa local
rpool copies 1 local
rpool version 5 -
rpool utf8only off -
rpool normalization none -
rpool casesensitivity sensitive -
rpool vscan off default
rpool nbmand off local
rpool sharesmb off local
rpool refquota none default
rpool refreservation 20G local
rpool guid 11335222168571905936 -
rpool primarycache all local
rpool secondarycache all local
rpool usedbysnapshots 333G -
rpool usedbydataset 316G -
rpool usedbychildren 647G -
rpool usedbyrefreservation 0B -
rpool logbias latency local
rpool objsetid 54 -
rpool dedup edonr,verify local
rpool mlslabel none default
rpool sync standard local
rpool dnodesize 16k local
rpool refcompressratio 1.19x -
rpool written 74.9G -
rpool logicalused 1.12T -
rpool logicalreferenced 338G -
rpool volmode full local
rpool filesystem_limit none default
rpool snapshot_limit none local
rpool filesystem_count 2 local
rpool snapshot_count 76 local
rpool snapdev hidden default
rpool acltype nfsv4 local
rpool context none default
rpool fscontext none default
rpool defcontext none default
rpool rootcontext none local
rpool relatime on local
rpool redundant_metadata all local
rpool overlay off local
rpool encryption off default
rpool keylocation none default
rpool keyformat none default
rpool pbkdf2iters 0 default
rpool special_small_blocks 0 local
rpool snapshots_changed Sat Oct 15 9:00:01 2022 local |
i would like to make the variables simple by nature so for example
rpoolencryption=off
rpoorelatime=on
rpoolsnapdev=on
I guess i pretty much want to merge col 1 and 2 and make it =col3 for the variable.
so far i got this but which does that but i need to xargs it to go back to the same file the script is running at on a specific line. like xargs -I {} echo {} > $0 but at a specific line?
| Code: | | zfs get all rpool | awk '{print $1$2"="$3}' |
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Hu
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Joined: 06 Mar 2007
Posts: 23026
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| Posted: Sat Oct 15, 2022 5:34 pm Post subject: Re: Set multiple variables from output of 1 command? |
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Can you get the output to be less ambiguous? As shown, some of your lines have 4 columns. Some have many more columns, such as creation, which has the following columns:- rpool
- creation
- Sat
- Jun
- 11
- 20:36
- 2022
- -
The easiest fix for that would be to get the output to be printed using tab separators, assuming tabs never appear in the value field.
Ignoring that problem, this is easy:
bash required due to process substitution: | Code: | while read name property value source; do
printf -v "$name$property" '%s' "$value"
done < <( zfs get all rpool ) |
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finalturismo
Guru
Joined: 06 Jan 2020
Posts: 410
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| Posted: Sat Oct 15, 2022 6:18 pm Post subject: Re: Set multiple variables from output of 1 command? |
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| Hu wrote: | Can you get the output to be less ambiguous? As shown, some of your lines have 4 columns. Some have many more columns, such as creation, which has the following columns:- rpool
- creation
- Sat
- Jun
- 11
- 20:36
- 2022
- -
The easiest fix for that would be to get the output to be printed using tab separators, assuming tabs never appear in the value field.
Ignoring that problem, this is easy:
bash required due to process substitution: | Code: | while read name property value source; do
printf -v "$name$property" '%s' "$value"
done < <( zfs get all rpool ) |
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wow thanks |
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Hu
Administrator
Joined: 06 Mar 2007
Posts: 23026
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| Posted: Sat Oct 15, 2022 7:01 pm Post subject: |
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| If you can't get zfs to produce machine-readable output, you could try to slice up the output based on column positions. That is fairly simple if we assume fixed width columns. It is rather messier if we assume variable width columns, and need to dynamically detect column width from the header. It is unreliable if the column headers are of fixed position, and the excessively wide fields simply overflow into the next column. |
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pjp
Administrator
Joined: 16 Apr 2002
Posts: 20581
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| Posted: Tue Oct 18, 2022 10:46 pm Post subject: |
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You may want to check output options. At least for a seemingly old version (2010 maybe?), there are/were options -H and -o.
| Quote: | Querying ZFS Properties for Scripting
The zfs get command supports the -H and -o options, which are designed for scripting. You can use the -H option to omit header information and to replace white space with the Tab character. Uniform white space allows for easily parseable data. You can use the -o option to customize the output in the following ways:
The literal name can be used with a comma-separated list of properties as defined in the Introducing ZFS Properties section.
A comma-separated list of literal fields, name, value, property, and source, to be output followed by a space and an argument, which is a comma-separated list of properties. |
| Code: | | https://docs.ora cle.com/ cd/E19253-01/819-5461/gazuk/index.html |
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