A CLI and a REPL for managing LevelDB instances.
This repo is a fork of lev, originally to make those changes available from NPM
$ npm install -g lev2
These all match the parameters used with levelup. The default encoding for the database is set to json.
Get a value
lev --get foo
Put a value
lev --put foo --value bar
Delete a value
lev --del foo
Can be used in combination with --keys, or --all, or implicit --all, to generate a stream of delete operations to be passed to the lev --batch command
lev --keys --del | lev --batch
lev --all --del | lev --batch
lev --gte abc --lte abd --del | lev --batch
Put or delete several values, using levelup batch syntax
lev --batch '[
{"type":"del","key":"a"},
{"type":"put","key":"b","value":"123"},
{"type":"put","key":"c","value":"456"}
]'
or from a file
# there should be one entry per line
# either as valid JSON
echo '[
{"type":"del","key":"a"},
{"type":"put","key":"b","value":"123"},
{"type":"put","key":"c","value":"456"}
]' > ops.json
# or as newline-delimited JSON
echo '
{"type":"del","key":"a"}
{"type":"put","key":"b","value":"123"}
{"type":"put","key":"c","value":"456"}
' > ops.json
lev --batch ./operations.json
If the type is omitted, defaults to put, which allows to use the command to do imports/exports, in combination with --all:
# export
lev --all > leveldb.export
# import
lev /tmp/my-new-db --batch leveldb.export
If it's a large export, you can use compress it on the fly
# export
lev --all | gzip -9 > leveldb.export.gz
# import
gzip -d < leveldb.export.gz | lev /tmp/my-new-db --batch
The --batch option can also be used to delete key/values by range in 2 steps:
# 1 - collect all the key to delete
lev --prefix 'foo' --del > ./deletion_operations
# 2 - pass the file as argument to the --batch option
lev --batch ./deletion_operations
The same can be done with --match
lev --match '*foo*' --del > ./deletion_operations
List all the keys in the current range
lev --keys
Can be used in combination with --del to generate a stream of delete operations
lev --keys --del | lev --batch
List all the values in the current range. Emit as a new-line delimited stream of json.
lev --values
List all the keys and values in the current range. Emit as a new-line delimited stream of json.
lev --all
It can be used to create an export of the database, to be imported with --batch
lev --all > leveldb.export
lev /tmp/my-new-db --batch leveldb.export
It can be used in combinaision with other options, but can then also be omitted as its the default stream mode
lev --all --prefix 'foo'
# is equivalent to
lev --prefix 'foo'
Start the range at keys greater than or equal to <key-pattern>. For strictly greater than, use --gt.
# output all keys and values after 'foo' (implicit --all)
lev --gte 'foo'
# output all keys after 'foo'
lev --keys --gte 'foo'
# the same for values
lev --values --gte 'foo'
For keys and values strictly greater tha
End the range at keys lower than or equal to <key-pattern>. For strictly lower than, use --.
# output all keys and values before 'fooz' (implicit --all)
lev --lte 'fooz'
# output all keys before 'fooz'
lev --keys --lte 'fooz'
# the same for values
lev --values --lte 'fooz'
# output all keys between 'foo' and 'fooz'
lev --keys --gte 'foo' --lte 'fooz'
# which is equivalent to
Get all entries for which the key starts by a given prefix
# get all the keys starting by foo
lev --keys --prefix 'foo'
# which is equivalent to
lev --keys --gte 'foo' --lte 'foo\uffff'
Filter results by a pattern applied on the keys
lev --keys --match 'f*'
lev --values --match 'f*'
lev --all --match 'f*'
# Equivalent to
lev --match 'f*'
See minimatch doc for patterns
Limit the number of records emitted in the current range.
lev --keys --limit 10
lev --values --prefix 'foo' --limit 100
lev --match 'f*' --limit 10
Reverse the stream.
lev --keys --reverse
lev --keys --prefix 'foo' --limit 100 --reverse
Output the count of results in the selected range
# Count all the key/value pairs in the database
lev --count
# Counts the keys and values between 'foo' and 'fooz'
lev --prefix 'foo' --count
Specify the encoding for the values (Defaults to 'json').
lev --values --valueEncoding buffer
Specify the path to the LevelDB to use. Defaults to the current directory.
lev --location /tmp/test-db --keys
# Equivalent to
lev /tmp/test-db --keys
Pass results in a map function
lev --keys --map 'key => key.split(":")[1]'
lev --all --map 'data => data.value.replace(data.key, "")'
# in ./map_fn.js
module.exports = key => key.split(":")[1]
lev --keys --map ./map_fn.js
If the function, returns null or undefined, the result is filtered-out
This can be used to update the whole database:
# Create a map function that returns an object with the key and an updated value
echo 'module.exports = ({ key, value }) => ({
key,
value: value.replace('foo', 'bar')
})' > ./update_values.js
# Create an updated export of the database
lev --map ./update_values.js > ./updated_db
# And re-import
lev --batch ./updated_db
Start the REPL
# in the current directory
$ lev .
# somewhere else
$ lev path/to/db
Use upper or lower case for the following commands.
Get a key from the database.
Put a value into the database. If you have keyEncoding or valueEncoding
set to json, these values will be parsed from strings into json.
Delete a key from the database.
Get all the keys in the current range.
Defines the start of the current range. You can also use GT or GTE.
Defines the end of the current range. You can also use LT or LTE.
Limit the number of records in the current range (defaults to 5000).
Reverse the records in the current range.
FAQs
CLI for LevelDB
The npm package lev2 receives a total of 68 weekly downloads. As such, lev2 popularity was classified as not popular.
We found that lev2 demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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