arrow key via stdin

Question

I'm trying to send an arrow key via the stdin to the bash:

cat | /bin/bash

then i am typing "echo hi" => "hi" appears on the console (of course without the quotes) then i press the arrow key up => ^[[A command not found appears

Is it possible to send an arrow key to an program via the stdin ?

The reason why i am asking is: I want to control the bash from another programm. I would like to send arrow keys to the bash

Answer 1

What you really should be doing is create a pseudo-tty device (using openpty() or similar), start bash on that PTY, and send your key strokes through that PTY device. See the section on “Pseudo-Terminals” in the GNU C Library Manual.

Answer 2

Don't use cat . Use the Bash builtin read command with the -e option to enable readline support.

# version 1
while IFS="" read -r -e -d $'\n' line; do printf '%s\n' "$line"; done | /bin/bash

# version 2
#set -o pipefail
# kill 0: kill process group
(
while IFS="" read -r -e -d $'\n' line; do 
   #trap 'trap - EXIT HUP INT QUIT PIPE TERM ERR; kill $PPID' EXIT HUP INT QUIT PIPE TERM ERR 
   trap 'trap - EXIT HUP INT QUIT PIPE TERM ERR; kill 0' EXIT HUP INT QUIT PIPE TERM ERR 
   printf '%s\n' "$line" >> ~/.bash_history
   history -n
   printf '%s\n' "$line" 
done 
) | (trap 'trap - EXIT HUP INT QUIT PIPE TERM ERR; kill 0' EXIT HUP INT QUIT PIPE TERM ERR; /bin/bash)
#) | (trap 'trap - EXIT HUP INT QUIT PIPE TERM ERR; kill $PPID' EXIT HUP INT QUIT PIPE TERM ERR; /bin/bash)

Answer 3

尝试使用-i开关启动bash。