/test.mp3:
$ fq
exitcode: 2
stderr:
Usage: fq [OPTIONS] [--] [EXPR] [FILE...]
$ fq -h
fq - jq for files
Tool, language and format decoders for exploring 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
--options                Show all options
--raw-input,-R           Read raw input strings (don't decode)
--raw-output,-r          Raw string output (without quotes)
--rawfile NAME PATH      Set variable $NAME to string content of file
--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
exitcode: 2
stderr:
Usage: fq [OPTIONS] [--] [EXPR] [FILE...]
$ 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
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
bzip2                bzip2 compression
dns                  DNS packet
elf                  Executable and Linkable Format
exif                 Exchangeable Image File Format
flac                 Free Lossless Audio Codec file
flac_frame           FLAC frame
flac_metadatablocks  FLAC metadatablocks
flac_picture         FLAC metadatablock picture
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
id3v1                ID3v1 metadata
id3v11               ID3v1.1 metadata
id3v2                ID3v2 metadata
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
ogg                  OGG file
ogg_page             OGG page
opus_packet          Opus packet
png                  Portable Network Graphics file
protobuf             Protobuf
protobuf_widevine    Widevine protobuf
pssh_playready       PlayReady PSSH
raw                  Raw bits
tar                  Tar archive
tiff                 Tag Image File Format
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
$ fq --options
{
  "addrbase": 16,
  "arg": [],
  "argjson": [],
  "array_truncate": 50,
  "bits_format": "snippet",
  "byte_colors": "0-0xff=brightwhite,0=brightblack,32-126:9-13=white",
  "color": false,
  "colors": "array=white,dumpaddr=yellow,dumpheader=yellow+underline,error=brightred,false=yellow,index=white,null=brightblack,number=cyan,object=white,objectkey=brightblue,string=green,true=yellow,value=white",
  "compact": false,
  "decode_file": [],
  "decode_format": "probe",
  "decode_progress": false,
  "depth": 0,
  "display_bytes": 16,
  "expr": ".",
  "expr_eval_path": "arg",
  "expr_file": null,
  "filenames": [
    "-"
  ],
  "include_path": null,
  "join_string": "\n",
  "line_bytes": 16,
  "null_input": false,
  "raw_output": false,
  "raw_string": false,
  "rawfile": [],
  "repl": false,
  "show_formats": false,
  "show_help": false,
  "show_options": true,
  "sizebase": 10,
  "slurp": false,
  "string_input": false,
  "unicode": false,
  "verbose": false
}
$ 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