ugrep as grep: -o with wide context bounds like .{0,140} fails with "exceeds complexity limits"

Symptom: on a machine where grep resolves to ugrep (common with some shell setups), a context-extraction search such as grep -i -o -E ".{0,140}alternat.{0,160}" file.csv aborts with ugrep: error: error at position 87 ... exceeds complexity limits. ugrep expands . to a UTF-8 multibyte class, so large bounded repeats blow past its DFA limit; GNU grep would accept the same pattern.

Fixes: (1) use smaller bounds (e.g. .{0,60}), (2) use grep -n pattern and print surrounding lines with -C, or (3) do it in Python, which has no such limit and handles CSV cells with embedded newlines:

import re
t = open(f, encoding="utf-8").read()
for m in re.finditer(r"alternat", t, re.I):
    print(t[max(0, m.start()-160):m.end()+180].replace("\n", " "))

Check which grep you have with grep --version | head -1 before relying on GNU-only behaviour.