File merging consists in creating one output product from two input of the same kind.
This operation is requested with merge
which requires a secondary input file, this one is to serve as the reference point in the Merge(A, B) operation.
Example (1): attempting to merge Navigation RINEX into Observation is an invalid operation
rinex-cli \
--fp data/ESBC00DNK_R_20201770000_01D_MN.rnx.gz \
merge data/ESBC00DNK_R_20201770000_01D_30S_MO.crx.gz
Example (2): merging two CRINEX files together.
rinex-cli \
--fp data/MOJN00DNK_R_20201770000_01D_30S_MO.crx.gz \
merge data/ESBC00DNK_R_20201770000_01D_30S_MO.crx.gz