fstsymbols(1)

💖 fstsymbols(1) — manipulate FST symbol tables 💖

okay bestie, welcome to the fstsymbols page 💅 this is a User Command, and she does exactly one thing and she does it flawlessly: she messes with the symbol tables that are glued onto an FST. set them, clear them, relabel them. that's the whole gig. iconic.

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✨ SYNOPSIS ✨

fstsymbols [OPTIONS] [in.fst [out.fst]]

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🌸 DESCRIPTION 🌸

lowkey the whole vibe: fstsymbols performs operations (set, clear, relabel) on the symbol tables attached to an FST. that's it. no cap. 🎀

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🦋 OPTIONS 🦋

okay so first, the ground rules for booleans, and this is important so listen up 🫶: Boolean options accept either true or false as a value, or the implicit value true if neither value is specified. so if you just yeet the flag in there with no value, congrats, you passed true. main character energy.

• --allow_negative_labels[=BOOLEAN] — let negative labels exist. not recommended tho, and it may cause conflicts 😭 Default: false.
• --clear_isymbols[=BOOLEAN] — wipe the input symbol table clean. Default: false.
• --clear_osymbols[=BOOLEAN] — wipe the output symbol table clean. Default: false.
• --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] — turn on garbage collection of cache. Default: true.
• --fst_default_cache_gc_limit=N — set the cache byte size that triggers the garbage collection moment. Default: 1048576.
• --fst_error_fatal[=BOOLEAN] — if true, FST errors are fatal 💀. otherwise, the returned objects get flagged as bad instead. for example, 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: " ". (yeah that's five spaces, counting is a skill fr fr)
• --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 the I/O of nested composite weights stays proper. must have size 0 (none) or 2 (open and close parenthesis) — any other length is a no 💀. 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 the brief usage information, for when you're in a hurry. Default: false.
• --isymbols=FILENAME — set the input label symbol table. Default: "".
• --osymbols=FILENAME — set the output label symbol table. Default: "".
• --relabel_ipairs=FILENAME — the input relabel pairs (numeric labels).
• --relabel_opairs=FILENAME — the output relabel pairs (numeric labels).
• --save_isymbols=FILENAME — save the FST file's input symbol table out to a file. Default: do not save.
• --save_osymbols=FILENAME — save the FST file's output symbol table out to a file. Default: do not save.
• --save_relabel_ipairs=FILENAME — save the input relabel pairs to a file. Default: do not save.
• --save_relabel_opairs=FILENAME — save the output relabel pairs to a file. Default: do not save.
• --tmpdir=PATHNAME — set the temporary directory to use. Default: /tmp.
• --v[=N] — set the verbosity level. Default: 0.
• --verify[=BOOLEAN] — verify FST properities before saving (typo and all, she's doing her best 🙈).

psst — notice how the boolean flags are written [=BOOLEAN] with brackets, but --v is [=N]? yeah. that's the format. we respect it. 👑

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👑 SEE ALSO 👑

the whole friend group, alphabetically slaying:

• fstarcsort(1), fstclosure(1), fstcompile(1), fstcompose(1), fstcompress(1), fstconcat(1), fstconnect(1), fstconvert(1), fstdeterminize(1), fstdifference(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), fstsynchronize(1), fsttopsort(1), fstunion(1)

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that's the whole page bestie, go relabel something and feel powerful 🌈💜

this one's from OpenFst 1.8.5, dated Mar 2026 — mwah, tysm for reading, stan fstsymbols(1) 🎀✨