File types

peek auto-detects the file type by extension and magic bytes. Where the detected type has a dedicated viewer, that viewer runs; otherwise peek falls back to the hex dump.

CategoryFormats
Source code100+ languages via syntect (Rust, Python, Go, TS, …)
MarkupMarkdown, HTML, XML, SQL
Email.eml messages, .mbox mailboxes
Calendar/contactsiCalendar (.ics), vCard (.vcf)
NotebooksJupyter (.ipynb)
Structured dataJSON / JSONC / JSON5 / JSONL, YAML, TOML, XML
Tabular dataCSV, TSV (aligned table view)
DatabasesSQLite (schema listing + streaming row viewer)
Spreadsheets.xlsx, .xlsm, .ods (sheet listing → table per sheet)
Presentations.pptx, .pptm, .ppsx, .odp (slide text); .key (preview)
DocumentsDOCX, ODT, RTF
PDF / Illustrator.pdf, .ai (paged render + text + embeds)
EPS / PostScript.eps, .ps (embedded preview + Ghostscript render + DSC info)
EbooksEPUB
ImagesPNG, JPEG, GIF, WebP, BMP, TIFF, ICO, AVIF, PNM, TGA, EXR, QOI, DDS
VectorSVG (incl. CSS @keyframes animation)
AudioMP3, FLAC, Ogg, Opus, WAV, MPEG-4, AAC, AIFF, CAF, MKA, WMA
ArchivesZIP, tar (+gz/bz2/xz/zst/lz4/br), 7-Zip, cpio, ar / .deb
Compressiongzip, bzip2, xz, zstd, lz4, brotli (bare wrappers)
Comic archivesCBZ
Disk imagesISO 9660, DMG (UDIF trailer)
FilesystemDirectories (one-level listing)
ExecutablesELF, Mach-O, PE / COFF, WebAssembly (.wasm) object files
Java classfiles.class files — header, fields, methods
CertificatesPEM X.509 / CSR / CRL / keys / OpenSSH public keys
FontsTrueType, OpenType, TTC / OTC collections, WOFF / WOFF2 (metadata + specimen render)
.DS_StoreApple Finder store — records table (icon / window / view settings)
Binary / unknownHex dump (hexdump -C style)

Detection logic: crates/peek-detect/.