Append text to file from command line without using io redirection

Question

How can we append text in a file via a one-line command without using io redirection?

Answer 1

If you just want to tack something on by hand, then the sed answer will work for you. If instead the text is in file(s) (say file1.txt and file2.txt):

Using Perl:

perl -e 'open(OUT, ">>", "outfile.txt"); print OUT while (<>);' file*.txt

N.B. while the >> may look like an indication of redirection, it is just the file open mode, in this case "append".

Answer 2

If you don't mind using sed then,

$ cat test 
this is line 1
$ sed -i '$ a\this is line 2 without redirection' test 
$ cat test 
this is line 1
this is line 2 without redirection

As the documentation may be a bit long to go through, some explanations :

• -i means an inplace transformation, so all changes will occur in the file you specify
• $ is used to specify the last line
• a means append a line after
• \ is simply used as a delimiter

Answer 3

You can use the --append feature of tee:

cat file01.txt | tee --append bothFiles.txt 
cat file02.txt | tee --append bothFiles.txt 

Or shorter,

cat file01.txt file02.txt | tee --append bothFiles.txt 

I assume the request for no redirection (>>) comes from the need to use this in xargs or similar. So if that doesn't count, you can mute the output with >/dev/null.

Answer 4

You can use Vim in Ex mode:

ex -sc 'a|BRAVO' -cx file

1. a append text

2. x save and close