Just use dd+task_mmap()+ELFrelocation impl ULPatch??

[Rtoax]

1. 2862 is bash pid
2. 0x55857ed4fb70 is address of ps1_prompt

(gdb) print (char *)ps1_prompt 
$1 = 0x55857ed4fb70 "hello$ \n;D;$?\\e\\\\\\e]133;A\\e\\\\\\]${PROMPT_START@P}\\[\\e[${PROMPT_COLOR}${PROMPT_HIGHLIGHT:+;$PROMPT_HIGHLIGHT}m\\]${PROMPT_USERHOST@P}\\[\\e[0m\\]${PROMPT_SEPARATOR@P}\\[\\e[${PROMPT_DIR_COLOR-${PROMPT_COLOR}}"...

dd if=./a.dat of=/proc/2862/mem oseek=$(printf %ld 0x55857ed4fb70) bs=1 count=9