How can I remove the last character of a file in unix?

Question

Say I have some arbitrary multi-line text file:

sometext
moretext
lastline

How can I remove only the last character (the e, not the newline

Answer 1

sed 's/.$//' filename | tee newFilename

This should do your job.

Answer 2

If the goal is to remove the last character in the last line, this awk should do:

awk '{a[NR]=$0} END {for (i=1;i<NR;i++) print a[i];sub(/.$/,"",a[NR]);print a[NR]}' file
sometext
moretext
lastlin

It store all data into an array, then print it out and change last line.