Data Processing

To remove any trailing whitespace from a file, we can use sed. By using in-place editing -i, sed can be provided with a search-and-replace action to filter out whitespace at the end of each line. By replacing it with nothing, it will effectively be removed. sed -i 's/[[:space:]]*$//' mytextfile.txt Explanation -i = inline file edit s/ = search [[:space:]]*$ = search one or more occurences of whitespace just before the end of the line // = No text, so any occurences of the whitespace will be emptied The [[:space:]] is called a character class and refers to space characters.

To insert a line at the beginning of a file, we can use sed to achieve this task. By using in-place editing -i, we can instruct sed to make a change to an existing file. The next step is to tell sed what to change or insert and at what place. sed -i '1i # New first line' mytextfile.txt Explanation -i = inline file edit 1i = insert at first line # New first line = Text to add