# ecpg > Embedded SQL preprocessor for C programs. > More information: . - Preprocess a specific file: `ecpg {{input.pgc}}` - Preprocess from `stdin` and output to `stdout`: `ecpg -o - -` - Preprocess from `stdin` and write to a file: `cat input.pgc | ecpg -o output.c -` - Preprocess and specify an output file: `ecpg -o {{output.c}} {{input.pgc}}` - Preprocess a header file (`.pgh` extension): `ecpg {{input.pgh}}` - Preprocess in a specific compatibility mode: `ecpg -C {{INFORMIX|INFORMIX_SE|ORACLE}} {{input.pgc}}` - Preprocess with autocommit enabled: `ecpg -t {{input.pgc}}`