marc21-select(1)

NAME

marc21-select — Transforms records into CSV or TSV format

SYNOPSIS

marc21 select [OPTIONS] <QUERY> [PATH]…\

DESCRIPTION

This command allows you to efficiently transform records into a rectangular table schema. By default, the output is in CSV format.

ARGUMENTS

<QUERY>: A MARC-21 query expression.

OPTIONS

-H, --header <header>: Insert a header row before the data. The header should be entered as a comma-separated list. Leading and trailing spaces in each column are automatically removed.
--tsv: Write output tab-separated (TSV)
-o, --output <path>: Write output to <path> instead of stdout. If the filename ends in .tsv or .tsv.gz, the output is automatically saved in TSV format. The output is gzip-compressed when the filename ends with .gz.

-l, --limit <n>: Limit the result to first <n> records (a limit value 0 means no limit)
-s, --skip-invalid: Skip invalid records that can’t be decoded
--strsim-threshold: The minimum score for string similarity comparisons (0 <= score <= 100)
--where: An expression for filtering records
--filter-normalization <form>: Transliterate the given filter or query expression into the specified Unicode normal form. Possible values: nfd, nfkd, nfc, nfkc. This option can also be specified by setting the environment variable MARC21_FILTER_NORMALIZATION.

COMMON OPTIONS

-p, --progress: If set, show a progress bar
-c, --compression: Specify compression level (0..=9)

EXIT STATUS

0 — Command succeeded.
1 — Command failed.

This example demonstrates how to create a table in CSV format, where the first column (cn) contains the control number of the record, the second column (label) contains the name of the authority record, and the third column (gndsys) contains the GND classification. Since multiple notations from the GND classification system can be assigned to a single data record, the output generates multiple rows for these data records.

$ marc21 select -ps --header 'cn,label,gndsys' \
    '001, 150.a, 065{ a | 2 == "sswd" }' DUMP.mrc.gz -o out.csv
207,505 records, 0 invalid | 102,139 records/s, elapsed: 00:00:01  

$ head -10 out.csv
cn,label,gndsys
040000028,A 302 D,31.9b
040000230,Aargauer,17.1
040000303,Abakus,28
040000443,Abbildung,28
040000540,ABC-Schutz,7.15a
040000540,ABC-Schutz,8.4
040000567,ABC-Waffen,8.4
040000656,Abdichtung,31.3b
040000656,Abdichtung,31.6

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