stdbuf

Run a command with modified buffering operations for its standard streams. More information: https://www.gnu.org/software/coreutils/stdbuf.

• Change stdin buffer size to 512 KiB:
  stdbuf --input={{512K}} {{command}}
• Change stdout buffer to line-buffered:
  stdbuf --output={{L}} {{command}}
• Change stderr buffer to unbuffered:
  stdbuf --error={{0}} {{command}}