Remove last lines from file with shell, bash, csh, zsh

To remove the last X lines of a file, the easiest way is to use head combined with wc -l

# get the output of wc -l (which counts the lines of a file), parse them to a number 
# and extract 3 (the number of lines you want to remove)
philipp@Host% set CMD1="expr `cat longFile.csv | wc -l` - 3"

# now remove last 3 lines by using head and redirect them to your file
philipp@Host% head -n  `$CMD1` Segment5_Contexts.csv > shortFile.csv