Remove escape sequence characters like newline, tab and carriage return from JSON file

A pure jq solution:

$ jq -r '.content.message | gsub("[\\n\\t]"; "")' file.jsonERROR LALALLAERROR INFO NANANANSOME MORE ERROR INFOBABABABABABBA BABABABA ABABBABAA BABABABAB

If you want to keep the enlosing " characters, omit -r.

^{Note: peak's helpful answer contains a generalized regular expression that matches all control characters in the ASCII and Latin-1 Unicode range by way of a Unicode category specifier, \p{Cc}. jq uses the Oniguruma regex engine.}

Other solutions, using an additional utility, such as sed and tr.

Using sed to unconditionally remove escape sequences \n and t:

$ jq '.content.message' file.json | sed 's/\\[tn]//g'"ERROR LALALLAERROR INFO NANANANSOME MORE ERROR INFOBABABABABABBA BABABABA ABABBABAA BABABABAB"

Note that the enclosing " are still there, however.To remove them, add another substitution to the sed command:

$ jq '.content.message' file.json | sed 's/\\[tn]//g; s/"\(.*\)"/\1/'ERROR LALALLAERROR INFO NANANANSOME MORE ERROR INFOBABABABABABBA BABABABA ABABBABAA BABABABAB

A simpler option that also removes the enclosing " (note: output has no trailing \n):

$ jq -r '.content.message' file.json | tr -d '\n\t'ERROR LALALLAERROR INFO NANANANSOME MORE ERROR INFOBABABABABABBA BABABABA ABABBABAA BABABABAB

Note how -r is used to make jq interpolate the string (expanding the \n and \t sequences), which are then removed - as literals - by tr.

With your input, the following incantation:

$ jq 'walk(if type == "string" then gsub("\\p{Cc}"; "<>") else . end)' 

produces:

{  "HOSTNAME": "server1.example",  "content": {    "message": "ERROR LALALLA<>ERROR INFO NANANAN<>SOME MORE ERROR INFO<>BABABABABABBA<> BABABABA<> ABABBABAA<><> BABABABAB<><>"  },  "level": "WARN",  "level_value": 30000,  "logger_name": "server1.example.adapter"}

Of course, the above invocation is just illustrative:

• you might not need to use walk/1 at all. (walk/1 walks the input JSON.)
• you might want to use a different character class, or specify a pipeline of gsub/2 invocations.
• if you simply want to excise the control characters, specify "" as the second argument of gsub/2.

If you do want to use walk/1 but your jq does not have it, then simply add its definition (easily available on the web, such as here) before its invocation.