Use sed to delete a character

Shell Programming and Scripting
1

I built a 12 million record file and made a mistake, one field is 1 character too long.

The record is 40 bytes and ends always in 999. I am trying to delete the 37 character in each record. Is this possible without doing a cut and paste.

2

To delete the 37-th character on every line [on Solaris for example]:

/bin/echo '%s/^\(.\{36\}\).\(.*\)$/\1\2/g\nwq!' | /usr/xpg4/bin/ex -s btomas.txt