Oh and another one I use all the time is as an "identity transform" when selecting between filters, e.g. dostuff () { if [[ $1 = clean ]]; then

Oh and another one I use all the time is as an "identity transform" when selecting between filters, e.g. dostuff () { if [[ $1 = clean ]]; then grep -v dirt else cat fi | do_other_stuff } See also https://www.in-ulm.de/~mascheck/various/uuoc/ https://www.in-ulm.de/~mascheck/various/uuoc/ (via https://lobste.rs/s/rtvp2u/useful_uses_cat#c_0xpqkr https://lobste.rs/s/rtvp2u/useful_uses_cat#c_0xpqkr )