Unable to read more than 1024 chars on ZSH + MacOS

Question

Trying to read a long input into a variable from ZSH on MacOS.

    echo "URL: "
    read URL

input is always truncated to 1024 chars... if I try and type additional chars nothing happens.

Input is copy/pasted from PostMan, its an S3 signed upload URL
If I try and delete a few chars from the end (after pasting) I am only able to manually type as many chars as I deleted
I tried using the -n option to no avail (nothing gets read into the variable)

How can I read a long input? ~1500 chars

hm, interesting, it works for me (Linux, middle-mouse copy and paste into read, as well as writing into an fd and reading that: < <(for i in {1..1500}; do printf "%d" $(( i % 10 )); done; printf "\n") read URL, then printf '%s' $URL | wc yields 1500). — Marcus Müller, Mar 14 '24 at 14:06
Please edit your question to describe the way you're giving characters to the read URL command. Are you truly typing 1500 characters on your keyboard, or are you using a mouse to copy from one window (where the displayed text is wrapped) and paste into the window where your read command is running? Are there carriage return or Control-D characters in the URL you're typing? — Sotto Voce, Mar 14 '24 at 15:50
Related: Terminal does not accept pasted or typed lines of more than 1024 characters, and similarly on Linux Is there any limit on line length when pasting to a terminal in Linux? (4096 B) — ilkkachu, Mar 14 '24 at 20:10

score 0 · Answer 1 · answered Mar 14 '24 at 18:01

read itself just reads bytes from the terminal, it has no control over how the terminal reads those bytes. And the terminal has a limited line length which, as far as I recall, can't be changed easily (or at all?). The terminal's line editor is also very crude, just supporting backspace and not other editing commands.

Use vared instead. This is somewhat similar to read (but with different options), but it's specialized to reading from a terminal and it uses zsh's line editor. That makes it a lot more user-friendly, in addition to not having a line length limit.

URL=
vared -p "URL: " URL

vared always reads from the terminal, not from standard input. If you want to support reading input redirected from a file or pipe, check whether standard input is a terminal with the -t condition..

URL=
if [[ -t 0 ]]; then
  vared -p "URL: " URL
else
  read -r URL
fi

Unable to read more than 1024 chars on ZSH + MacOS

1 Answers1