On Rosh Chodesh and on Pesach after the first yom tov, most communities recite Hallel b'dilug ("half" Hallel). In most siddurim that I'm used to, the skipped-over portions are Psalms 115:1–11 and Psalms 116:1–11.
I am looking for sources that discuss what to do if one intended to say Hallel b'dilug but instead did not skip (some of) the sections above. There are several places of realisation I've identified that may or may not make a difference as to the answer:
- Somewhere in 115:1-11 — perhaps we skip ahead to 115:12?
- Between 115:11 and 115:12 — perhaps we skip the rest of 115?
- Somewhere in 115:12–18 — perhaps we complete what we started and skip as usual in 116, or perhaps we skip the rest of 115?
- Between 115 and 116 — perhaps we have to go back and redo 115 with the proper skip, or just skip as usual in 116?
- Somewhere in 116:1–11 — perhaps we skip ahead to 116:12?
- Between 116:11 and 116:12 — perhaps we skip the rest of 116?
- Somewhere in 116:12–19 — perhaps we skip the rest of 116, or we have to redo 116 with the proper skip, or redo from 115 with the proper skips?
- After 116 — perhaps we should skip somewhere in 117—118, or perhaps we need to redo from 115 (or 116) properly?
- At the end of Hallel — perhaps we need to redo from 115 (or 116), or the entire Hallel?
If any other realisation points (or possible next steps) are worth singling out, I would be interested to hear. An ideal answer would also determine whether it makes a difference whether we're discussing an individual vs. a community, or Hallel b'dilug with a bracha vs. without a bracha.