Ubuntu – How to add element to the gsettings array at the specific location (given by index)

bashcommand linedconfgsettings

I want to write a script that translates devilspie's window rules into compiz' rules. Compiz settings can be changed by gsettings keys in path org.compiz.profiles.unity.plugins.place. There are three keys: viewport-matches, viewport-x-values and viewport-y-values. Unfortunately each key is an array, and the index of the elements matters.

Gsettings lacks any support of array types other than rewriting whole array at once, and I need to place item in the array at the specific location (say, at the beginning, index '1').

I know, that if I don't care about the index, I can use

gsettings set ${schema} ${key} \"`gsettings get ${schema} ${key} | sed s/.$//`, ${value}]\"

The question complements How to remove element from gsettings array in script?

Best Answer

The following python3 script will insert new element(s) at a given index:

#!/usr/bin/env python3

import argparse
import subprocess

parser = argparse.ArgumentParser()
parser.add_argument("schema", help="gsettings shema", metavar="SCHEMA")
parser.add_argument("key", help="gsettings key", metavar="KEY")
parser.add_argument("index",
                    help="KEY array index where VALUE(s) need to be inserted",
                    metavar="INDEX", type=int)
parser.add_argument("value",
                    help="gsettings VALUE(s) to add to the KEY array",
                    metavar="VALUE", nargs='*')

args = parser.parse_args()

array = eval(subprocess.check_output(["gsettings", "get", args.schema, args.key]))
for v in sorted(args.value, reverse=True):
    try:
        value = eval(v)
    except NameError:
        value = v
    array.insert(args.index, value)
subprocess.call(["gsettings", "set", args.schema, args.key, str(array)])

Related Solutions

Ubuntu – How to dump all the manully altered dconf / gsettings keys

dconf provides such an option (Ref: man dconf)

To dump only user-altered (non-default) keys:
```
  dconf dump / > dump.dconf
```
To restore:
```
  dconf load / < dump.dconf
```

Ubuntu – How to remove element from gsettings array in script

Using bash for this task should be possible but I prefer doing complex array manipulations with a Python3 script:

#!/usr/bin/env python3

import argparse
import subprocess
import sys

parser = argparse.ArgumentParser()
parser.add_argument("schema", help="gsettings shema", metavar="SCHEMA")
parser.add_argument("key", help="gsettings key", metavar="KEY")
parser.add_argument("values",
                    help="gsettings value(s) to remove from the KEY array",
                    metavar="VALUE", nargs='*')
args = parser.parse_args()

array = eval(subprocess.check_output(["gsettings", "get", args.schema, args.key]))
for v in args.values:
    try:
        value = eval(v)
    except:
        value = v
    try:
        array.remove(value)
    except ValueError:
        print("Warning: {} not in {} {}".format(value, args.schema, args.key), file=sys.stderr)
subprocess.call(["gsettings", "set", args.schema, args.key, str(array)])

This script allow multiple values to be removed at the same time from the schema/key passed to the script.

Best Answer

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Ubuntu – How to dump all the manully altered dconf / gsettings keys

Ubuntu – How to remove element from gsettings array in script

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