How can I trim the contents of a text file?

Question

I want to remove all "blank" characters from the very beginning and the very end of a text file, including \n if exists. (basically mimicking the behaviour of trim() function of most programming languages, if the "file" was a big string).

Solution

Assuming you want to remove all spaces and newlines, not just the last newline, you can use tr:

tr -d '[[:space:]]' < file > file.trimmed

Or, more precisely:

tr -d '\t\n ' < file > file.trimmed

Comments

[Admin]

Can you provide a sample of the contents of the file?

[Admin]

Each line, or just the very beginning and end?

[Admin]

Just on the definition tack, I believe POSIX requires a newline at the end of a file in order to be called a “text” file. Just FYI.

[Admin]

Jeff: the very beginning and end. (main description updated)