SFDX script to retrieve profiles and perm sets with object CRUD and FLS

retrieve-object-perms.sh

#!/bin/bash

TARGET_ORG=$1

if [$TARGET_ORG == ""]; then
    echo Please specify a target username
    echo For a list of available usernames use: sfdx force:org:list
    exit 1
fi

rm -rf temp
mkdir temp
cd temp

# package.xml
echo '<?xml version="1.0" encoding="UTF-8"?>' > package.xml
echo '<Package xmlns="http://soap.sforce.com/2006/04/metadata">' >> package.xml

# Profiles
sfdx force:mdapi:listmetadata -m Profile -u $TARGET_ORG -f Profiles.json
echo "<types>" > Profiles.txt
cat Profiles.json | jq '[.[].fullName] | sort | .[] | "<members>" + . + "</members>"' -r >> Profiles.txt
echo "<name>Profile</name></types>" >> Profiles.txt
cat Profiles.txt >> package.xml

# PermissionSet
sfdx force:mdapi:listmetadata -m PermissionSet -u $TARGET_ORG -f PermissionSets.json
echo "<types>" > PermissionSets.txt
cat PermissionSets.json | jq '[.[].fullName] | sort | .[] | "<members>" + . + "</members>"' -r >> PermissionSets.txt
echo "<name>PermissionSet</name></types>" >> PermissionSets.txt
cat PermissionSets.txt >> package.xml

# Custom Objects
sfdx force:mdapi:listmetadata -m CustomObject -u $TARGET_ORG -f CustomObjects.json
echo "<types>" > CustomObjects.txt
cat CustomObjects.json | jq '[.[].fullName] | sort | .[] | "<members>" + . + "</members>"' -r >> CustomObjects.txt
echo "<name>CustomObject</name></types>" >> CustomObjects.txt
cat CustomObjects.txt >> package.xml


echo '<version>45.0</version>' >> package.xml
echo '</Package>' >> package.xml

# retrieve metadata
sfdx force:mdapi:retrieve -s -k package.xml -r ./ -u $TARGET_ORG
unzip unpackaged.zip -d $TARGET_ORG
rm unpackaged.zip

cd ..
mkdir retrieve
mv temp/$TARGET_ORG retrieve/
rm -rf temp

run the script as below:
sh script.sh <username of the org>