fstdifference(1)

📦
version 1.8.5 · 5 versions
, in ubuntu stonking

💖 fstdifference — it's giving "subtract an unweighted DFA from an FSA" ✨

okay so bestie, welcome to fstdifference(1), a user command from the OpenFst squad 🫶 she's a little niche but she EATS, I promise.

🌸 NAME 🌸

fstdifference — subtract an unweighted DFA from an FSA. that's it, that's the whole job, and she does it flawlessly 💅

✨ SYNOPSIS ✨

fstdifference [OPTIONS] in1.fst in2.fst [out.fst]

like, in goes in1.fst, in goes in2.fst, and optionally out comes out.fst. three files, zero drama 💖

🦋 DESCRIPTION 🦋

Subtracts an unweighted DFA from an FSA.

no literally that's what the page says and it's lowkey iconic in how brief it is. you hand her an FSA and an unweighted DFA, she does the subtraction thing. periodt ✨

🎀 OPTIONS 🎀

heads up bestie: boolean options accept either true or false as a value, or the implicit value true if neither value is specified. so like, bare flag = yes, =false = no. iykyk 💅
  • --compose_filter[=TYPE] — sets the composition filter. pick from alt_sequence, auto, match, or sequence. default is auto. ngl auto just handles it for you, main character energy 🌟
  • --connect[=BOOLEAN] — trim the output. default: true 🎀
  • --fst_align[=BOOLEAN] — write FST data aligned where appropriate. default: false ✨
  • --fst_compat_symbols[=BOOLEAN] — require symbol tables to match when appropriate. default: true 💖
  • --fst_default_cache_gc[=BOOLEAN] — enable garbage collection of the cache. default: true 🧹✨
  • --fst_default_cache_gc_limit=N — set the cache byte size that triggers garbage collection. default: 1048576 🔢
  • --fst_error_fatal[=BOOLEAN] — if true, FST errors are fatal 😭 otherwise the returned objects get flagged as bad. like, FSTs come back with the kError property set to true, and FST weights get set so that Member() returns false. default: true 💀
  • --fst_field_separator=STRING — set the characters used as a separator between printed fields. default: " " (yes queen, five spaces, exactly as written) 🎀
  • --fst_read_mode=STRING — set the default file reading mode for mappable files. either "read" or "map". default: "read" 📖
  • --fst_verify_properties[=BOOLEAN] — verify fst properties queried by TestProperties. default: false 🔍
  • --fst_weight_parentheses=STRING — set the characters enclosing the first weight of a printed composite weight (think pair weight, tuple weight, and derived classes) so nested composite weights do their I/O properly. must have size 0 (none) or 2 (open and close parenthesis). default: no parentheses 🌈
  • --fst_weight_separator=CHARACTER — set the character separator between printed composite weights. default: comma 🍓
  • --help[=BOOLEAN] — show usage information. default: false 🫶
  • --helpshort[=BOOLEAN] — show brief usage information. default: false ⭐
  • --save_relabel_ipairs=FILENAME — save input relabel pairs to file. default: do not save 💾
  • --save_relabel_opairs=FILENAME — save output relabel pairs to file. default: do not save 💾
  • --tmpdir=PATHNAME — set the temporary directory to use. default: /tmp 🗂️
  • --v[=N] — set the verbosity level. default: 0 🔥

👑 SEE ALSO 👑

the whole OpenFst friend group, obviously, she doesn't run alone:

fstarcsort(1), fstclosure(1), fstcompile(1), fstcompose(1), fstcompress(1), fstconcat(1), fstconnect(1), fstconvert(1), fstdeterminize(1), fstdisambiguate(1), fstdraw(1), fstencode(1), fstepsnormalize(1), fstequal(1), fstequivalent(1), fstinfo(1), fstintersect(1), fstinvert(1), fstisomorphic(1), fstlinear(1), fstloglinearapply(1), fstmap(1), fstminimize(1), fstprint(1), fstproject(1), fstprune(1), fstpush(1), fstrandgen(1), fstrelabel(1), fstreplace(1), fstreverse(1), fstreweight(1), fstrmepsilon(1), fstshortestdistance(1), fstshortestpath(1), fstsymbols(1), fstsynchronize(1), fsttopsort(1), fstunion(1)

and that's the whole vibe check bestie 💖 this page is from OpenFst 1.8.5, dated Mar 2026. go subtract something, you absolute icon 👑✨

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