{
    "api": "YAML JSON TOON Database",
    "version": "1.0.0",
    "format": "json",
    "dataset": {
        "slug": "awk-reference",
        "title": "AWK Reference",
        "description": "Essential AWK commands, built-in variables, and common patterns.",
        "summary": "AWK one-liners and patterns for working with columns and records: printing fields, setting the field separator, built-in variables, conditionals, sums, pattern matching and functions, extended with last-field printing, de-duplication, line ranges, averages, maxima and substitutions.",
        "use_when": [
            "You need a one-line column or record transformation on text or CSV-like data.",
            "You need the idiom for a common AWK task."
        ],
        "caveats": [
            "AWK implementations differ (GNU awk, mawk, BSD awk); gawk-specific features are not portable.",
            "For quoted CSV with embedded commas, use a proper CSV tool; awk -F, splits naively."
        ],
        "related": [
            "sed-reference",
            "unix-text-processing-commands",
            "file-operations",
            "string-algorithms"
        ],
        "category": "Unix Commands",
        "category_slug": "unix-commands",
        "tags": "unix,awk,text-processing,scripting",
        "view_count": 0,
        "entry_count": 16,
        "fields": [
            {
                "section": "data",
                "field": "pattern",
                "type": "string",
                "example": "Print columns"
            },
            {
                "section": "data",
                "field": "command",
                "type": "string",
                "example": "awk '{print $1, $3}'"
            },
            {
                "section": "data",
                "field": "description",
                "type": "string",
                "example": "Print the 1st and 3rd fields of each line."
            }
        ]
    },
    "data": [
        {
            "pattern": "Print columns",
            "command": "awk '{print $1, $3}'",
            "description": "Print the 1st and 3rd fields of each line."
        },
        {
            "pattern": "Field separator",
            "command": "awk -F: '{print $1}' /etc/passwd",
            "description": "Use colon as delimiter; print 1st field."
        },
        {
            "pattern": "Built-in variables",
            "command": "NR, NF, FS, OFS, RS, ORS, FILENAME",
            "description": "NR=record number, NF=field count, FS=OFS=field sep, RS=record sep."
        },
        {
            "pattern": "Conditional print",
            "command": "awk '$3 > 100 {print $1}'",
            "description": "Print $1 only when $3 exceeds 100."
        },
        {
            "pattern": "Sum a column",
            "command": "awk '{sum += $2} END {print sum}'",
            "description": "Accumulate sum of column 2 and print at END."
        },
        {
            "pattern": "Pattern matching",
            "command": "awk '/error/ {print}' log.txt",
            "description": "Print lines matching the regex /error/."
        },
        {
            "pattern": "Functions",
            "command": "length(), sub(), gsub(), split(), systime()",
            "description": "Built-in string and time functions."
        },
        {
            "pattern": "Multi-character FS",
            "command": "awk -v FS=\"\\t\" '{print $2}'",
            "description": "Set field separator to tab using -v flag."
        },
        {
            "pattern": "Print last field",
            "command": "awk '{print $NF}' file",
            "description": "NF is the number of fields, so $NF is the last one."
        },
        {
            "pattern": "Remove duplicate lines",
            "command": "awk '!seen[$0]++' file",
            "description": "Prints each line only the first time it appears, preserving order."
        },
        {
            "pattern": "Print a line range",
            "command": "awk 'NR==2,NR==5' file",
            "description": "Prints lines 2 through 5 using the record-number variable NR."
        },
        {
            "pattern": "Average a column",
            "command": "awk '{s+=$2} END {print s/NR}' file",
            "description": "Accumulates column 2 and divides by the number of records at the end."
        },
        {
            "pattern": "Maximum of a column",
            "command": "awk 'NR==1 || $3>m {m=$3} END {print m}' file",
            "description": "Tracks the largest value seen in column 3."
        },
        {
            "pattern": "Substitute text",
            "command": "awk '{gsub(/foo/,\"bar\"); print}' file",
            "description": "Replaces all occurrences of foo with bar in each line."
        },
        {
            "pattern": "Count matching lines",
            "command": "awk '/error/ {n++} END {print n+0}' file",
            "description": "Counts lines containing 'error'; n+0 prints 0 when none match."
        },
        {
            "pattern": "Filter by field length",
            "command": "awk 'length($1) > 5' file",
            "description": "Prints lines whose first field is longer than five characters."
        }
    ]
}