Shell – append text with echo without new line

echoio-redirectionshelltext processing

I want to append text to file like echo "abc" >>file.txt.

But this add abc after new line

How can I add abc in the end of file with echo without new line?

Best Answer

Assuming that the file does not already end in a newline and you simply want to append some more text without adding one, you can use the -n argument, e.g.

echo -n "some text here" >> file.txt

However, some UNIX systems do not provide this option; if that is the case you can use printf, e.g.

printf %s "some text here" >> file.txt

(the initial %s argument being to guard against the additional text having % formatting characters in it)

From man echo (on macOS High Sierra):

-n

Do not print the trailing newline character. This may also be achieved by appending '\c' to the end of the string, as is done by iBCS2 compatible systems. Note that this option as well as the effect of '\c' are implementation-defined in IEEE Std 1003.1-2001 ("POSIX.1") as amended by Cor. 1-2002. Applications aiming for maximum portability are strongly encouraged to use printf(1) to suppress the newline character.

Related Solutions

Shell – Add text with echo but start with new line if file not empty

You can test to see if a file is empty by using unix test -s. Example below...

 if [ -s $file ]
then
   echo "File size is zero"
else
   echo "File size is not zero"
fi

Redirect content under a new line (without further syntax or arguments)

You don't need to write the cat line "the wrong way", this works just fine (though of course the arrows in the here-string still point in an odd direction):

$ cat <<< "some text" >> testfile
$ cat testfile
some text

As mentioned in the comments, the here-string adds a newline at the end, while with printf and echo you used \n in the front of the string. echo would usually add the tailing newline, just like the here-string, so if you need just that, echo should be fine (plus it's a builtin in most shells.)

All your commands work slightly differently with the newlines

cat >> file <<< "string"        # newline at end
printf "\nstring" >> file       # newline at beginning
echo -e "\nstring" >> file      # newline at beginning and at the end

Frankly, I think it's better to get used to the \n notation, but if you don't like it, there's always here-docs (both leading and tailing newlines here):

cat >> file <<EOF

some text
EOF

Best Answer

Related Solutions

Shell – Add text with echo but start with new line if file not empty

Redirect content under a new line (without further syntax or arguments)

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