apt output is different when executed alone in Bash shell and when output is redirected to files.
$ apt install ./*.deb --simulate 1>111.txt 2>222.txt
adding redirection results in text
WARNING: apt does not have a stable CLI interface. Use with caution in scripts. in file for stream 2, whereas running apt w/out redirection does not display this text in shell window.
Why output depends on redirection? Maybe
apt sees redirection as its` parameter? How can I write redirection to be unnoticed to other part of shell command line?
P.S. I saw it in Ubuntu 18 and
apt is specific app, but maybe the issue is general to Unix, so I put only
shell in tag.