$ fq
exitcode: 2
stderr:
Usage: fq [OPTIONS] [--] [EXPR] [FILE...]
$ fq -h
fq - jq for binary formats
Tool, language and decoders for inspecting binary data.
For more information see https://github.com/wader/fq

Usage: fq [OPTIONS] [--] [EXPR] [FILE...]

--arg NAME VALUE         Set variable $NAME to string VALUE
--argjson NAME JSON      Set variable $NAME to JSON
--color-output,-C        Force color output
--compact-output,-c      Compact output
--decode,-d NAME         Decode format (probe)
--decode-file NAME PATH  Set variable $NAME to decode of file
--formats                Show supported formats
--from-file,-f PATH      Read EXPR from file
--help,-h                Show help
--include-path,-L PATH   Include search path
--join-output,-j         No newline between outputs
--monochrome-output,-M   Force monochrome output
--null-input,-n          Null input (use input/0 and inputs/0 to read input)
--null-output,-0         Null byte between outputs
--option,-o KEY=VALUE    Set option, eg: color=true (use options/0 to see all options)
--raw-file NAME PATH     Set variable $NAME to string content of file
--raw-input,-R           Read raw input strings (don't decode)
--raw-output,-r          Raw string output (without quotes)
--repl,-i                Interactive REPL
--slurp,-s               Read (slurp) all inputs into an array
--version,-v             Show version
$ fq -i
null> ^D
$ fq -i . /test.mp3
mp3> ^D
$ fq -n
null
$ fq -ni
null> ^D
$ fq -n 123
123
$ fq -ni 123
number> ^D
$ fq -n "[1,2,3]"
[
  1,
  2,
  3
]
$ fq -nc "[1,2,3]"
[1,2,3]
$ fq --formats
aac_frame            Advanced Audio Coding frame
adts                 Audio Data Transport Stream
adts_frame           Audio Data Transport Stream frame
apev2                APEv2 metadata tag
ar                   Unix archive
av1_ccr              AV1 Codec Configuration Record
av1_frame            AV1 frame
av1_obu              AV1 Open Bitstream Unit
avc_annexb           H.264/AVC Annex B
avc_au               H.264/AVC Access Unit
avc_dcr              H.264/AVC Decoder Configuration Record
avc_nalu             H.264/AVC Network Access Layer Unit
avc_pps              H.264/AVC Picture Parameter Set
avc_sei              H.264/AVC Supplemental Enhancement Information
avc_sps              H.264/AVC Sequence Parameter Set
avro_ocf             Avro object container file
bencode              BitTorrent bencoding
bsd_loopback_frame   BSD loopback frame
bson                 Binary JSON
bzip2                bzip2 compression
cbor                 Concise Binary Object Representation
dns                  DNS packet
dns_tcp              DNS packet (TCP)
elf                  Executable and Linkable Format
ether8023_frame      Ethernet 802.3 frame
exif                 Exchangeable Image File Format
flac                 Free Lossless Audio Codec file
flac_frame           FLAC frame
flac_metadatablock   FLAC metadatablock
flac_metadatablocks  FLAC metadatablocks
flac_picture         FLAC metadatablock picture
flac_streaminfo      FLAC streaminfo
gif                  Graphics Interchange Format
gzip                 gzip compression
hevc_annexb          H.265/HEVC Annex B
hevc_au              H.265/HEVC Access Unit
hevc_dcr             H.265/HEVC Decoder Configuration Record
hevc_nalu            H.265/HEVC Network Access Layer Unit
icc_profile          International Color Consortium profile
icmp                 Internet Control Message Protocol
id3v1                ID3v1 metadata
id3v11               ID3v1.1 metadata
id3v2                ID3v2 metadata
ipv4_packet          Internet protocol v4 packet
jpeg                 Joint Photographic Experts Group file
json                 JSON
matroska             Matroska file
mp3                  MP3 file
mp3_frame            MPEG audio layer 3 frame
mp4                  MPEG-4 file and similar
mpeg_asc             MPEG-4 Audio Specific Config
mpeg_es              MPEG Elementary Stream
mpeg_pes             MPEG Packetized elementary stream
mpeg_pes_packet      MPEG Packetized elementary stream packet
mpeg_spu             Sub Picture Unit (DVD subtitle)
mpeg_ts              MPEG Transport Stream
msgpack              MessagePack
ogg                  OGG file
ogg_page             OGG page
opus_packet          Opus packet
pcap                 PCAP packet capture
pcapng               PCAPNG packet capture
png                  Portable Network Graphics file
protobuf             Protobuf
protobuf_widevine    Widevine protobuf
pssh_playready       PlayReady PSSH
raw                  Raw bits
sll2_packet          Linux cooked capture encapsulation v2
sll_packet           Linux cooked capture encapsulation
tar                  Tar archive
tcp_segment          Transmission control protocol segment
tiff                 Tag Image File Format
udp_datagram         User datagram protocol
vorbis_comment       Vorbis comment
vorbis_packet        Vorbis packet
vp8_frame            VP8 frame
vp9_cfm              VP9 Codec Feature Metadata
vp9_frame            VP9 frame
vpx_ccr              VPX Codec Configuration Record
wav                  WAV file
webp                 WebP image
xing                 Xing header
zip                  ZIP archive
$ fq -X
exitcode: 2
stderr:
error: -X: no such argument
$ fq --X
exitcode: 2
stderr:
error: --X: no such argument
$ fq -.
exitcode: 2
stderr:
error: -.: no such argument