read(1)

NAME
read -- read line of input into variables

  Synopsis

read [OPTIONS] [VARIABLES...]

  Description
read reads from standard input and stores the result in one or more shell variables. By default it reads one line terminated by a newline but options are available to read up to a null character and to limit each 'line' to a maximum number of characters.

The following options are available:

•   -c CMD or --command=CMD sets the initial string in the interactive mode command buffer to CMD.

•   -g or --global makes the variables global.

•   -i or --silent makes the characters typed obfuscated. This is useful for reading things like passwords or other sensitive information. Note that in bash the short flag is -s. We can't use that due to the existing use as an alias for --shell.

•   -l or --local makes the variables local.

•   -m NAME or --mode-name=NAME specifies that the name NAME should be used to save/load the history file. If NAME is fish, the regular fish history will be available.

•   -n NCHARS or --nchars=NCHARS causes read to return after reading NCHARS characters rather than waiting for a complete line of input (either newline or null terminated).

•   -p PROMPT_CMD or --prompt=PROMPT_CMD uses the output of the shell command PROMPT_CMD as the prompt for the interactive mode. The default prompt command is set_color green; echo read; set_color normal; echo '> '.

•   -P PROMPT_STR or --prompt-str=PROMPT_STR uses the string as the prompt for the interactive mode. It is equivalent to echo PROMPT_STR and is provided solely to avoid the need to frame the prompt as a command. All special characters in the string are automatically escaped before being passed to the echo command.

•   -R RIGHT_PROMPT_CMD or --right-prompt=RIGHT_PROMPT_CMD uses the output of the shell command RIGHT_PROMPT_CMD as the right prompt for the interactive mode. There is no default right prompt command.

•   -s or --shell enables syntax highlighting, tab completions and command termination suitable for entering shellscript code in the interactive mode.

•   -u or --unexport prevents the variables from being exported to child processes (default behaviour).

•   -U or --universal causes the specified shell variable to be made universal.

•   -x or --export exports the variables to child processes.

•   -a or --array stores the result as an array in a single variable.

•   -z or --null reads up to NUL instead of newline. Disables interactive mode.

read reads a single line of input from stdin, breaks it into tokens based on the IFS shell variable, and then assigns one token to each variable specified in VARIABLES. If there are more tokens than variables, the complete remainder is assigned to the last variable. As a special case, if IFS is set to the empty string, each character of the input is considered a separate token.

If -a or --array is provided, only one variable name is allowed and the tokens are stored as an array in this variable.

See the documentation for set for more details on the scoping rules for variables.

When read reaches the end-of-file (EOF) instead of the separator, it sets $status to 1. If not, it sets it to 0.

Fish has a default limit of 10 MiB on the number of characters each read will consume. If you attempt to read more than that $status is set to 122 and the variable will be empty. You can modify that limit by setting the FISH_READ_BYTE_LIMIT variable at any time including in the environment before fish starts running. This is a safety mechanism to keep the shell from consuming an unreasonable amount of memory if the input is malformed.

  Example
The following code stores the value 'hello' in the shell variable $foo.

echo hello|read foo

  This is a neat way to handle command output by-line:
printf '%s\n' line1 line2 line3 line4 | while read -l foo
                  echo 'This is another line: $foo'
              end