TopolearnTurning JSON into text other tools consume, such as CSV, log lines or shell arguments, is a classic jq job.
String interpolation puts values into text: "\(.name) is \(.age)". Any expression works inside \( ), and non-strings are converted to JSON text.
Common string functions:
split(", ")andjoin("-")convert between strings and arrays;ascii_downcase,ascii_upcase,ltrimstr("v"),rtrimstr(".json"),startswith,endswith.tostringandtonumberconvert;lengthcounts characters.- Regexes (PCRE-like, via Oniguruma):
test("^err"; "i")returns a boolean,capture("(?<user>\\w+)@(?<host>.+)")returns an object of named groups,sub(re; repl)andgsubreplace,scan(re)emits all matches. Backslashes must be doubled inside jq strings.
Format strings turn data into text safely:
@csvand@tsvturn an array into a CSV or TSV row, with correct quoting. Use with-r.@shquotes values for use as shell arguments,@uripercent-encodes,@base64/@base64dencode and decode,@htmland@jsonescape.- They also prefix a string:
@uri "https://x.io/q?s=\(.term)"encodes only the interpolated parts.
A typical report: jq -r '.[] | [.id, .name, .email] | @csv' produces a CSV file you can open in a spreadsheet.
Example
echo '[{"id":1,"name":"Ann Lee","email":"ann@x.io"},{"id":2,"name":"Bob, Jr","email":"BOB@X.IO"}]' > u.json
jq -r '.[] | "\(.id): \(.name)"' u.json # 1: Ann Lee 2: Bob, Jr
jq -r '.[] | [.id, .name, .email] | @csv' u.json # 1,"Ann Lee","ann@x.io"
# 2,"Bob, Jr","BOB@X.IO"
jq -c '.[] | .email | ascii_downcase | capture("(?<user>[^@]+)@(?<host>.+)")' u.json
# {"user":"ann","host":"x.io"} {"user":"bob","host":"x.io"}
jq -c 'map(.name | split(" ") | .[0])' u.json # ["Ann","Bob,"]
jq -r '.[] | select(.email | test("x\\.io$"; "i")) | .id' u.json # 1 2
jq -r '@uri "https://s.io/?q=\(.[0].name)"' u.json # https://s.io/?q=Ann%20LeeRemember
- "\(expr)" interpolates values into strings
- test, capture, sub, gsub, split, join for text work
- @csv/@tsv on arrays, @sh, @uri, @base64 for safe output
Watch out for
- Using @csv on an object or a string; it needs an array, so build one with [ ... ] first.