# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/(\b(?:G,C,D|A,B,C|E,C,D)|(?:[ABCDEFG](?:#|b)?)(?:\\/[ABCDEFG]b)?(?:(?:(?:maj|min|sus|add|aug|dim)(?:\d{0,2}(?:#\d{1,2}|sus\d)?)?)|(?:m\d{0,2}(?:(?:maj|add|#)\d{0,2})?)|(?:-?\d{0,2}(?:\([^)]*\)|#\d{1,2})?))?)/[${1}]/g;t' <<< "1er couplet:
Gm G
Mon enfant, nue sur les galets
G D7
Le vent dans tes cheveux defaits
Dsus Cmaj
Comme un printemps sur mon trajet
C Em
Un diamant tombé d'un coffret"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html