bash programming-append single line to end of file

pheasand · 12-12-2004, 08:52 AM

If I had a file .. /etc/group for example, how can I append a single line to the end of group? I've browsed the docs for sed and awk, and while sed seems to be the correct tool for the job, I can't locate an example of a single line append. Also, there isn't any single 'append' command for bash that I know of. I have a man page for an append command but it is a TCL built in command and not an executable. Any ideas?

-pheasand

homey · 12-12-2004, 09:06 AM

The >> will append to the end of a file ....

echo this is a test >> /home/myfile.txt

pheasand · 12-12-2004, 09:13 AM

While looking through more sed docs I found:
cat inFile | sed '$a/Text to append' > outFile

which appends: "Text to append" after the last line of text in inFile

-pheasand

massysett · 01-12-2006, 06:59 PM

Good tip--one typo, though: if you're using GNU sed, that should be a backslash.

Using this I put together a pipeline that allows me to decrypt a text file using gpg, add something to it, and re-encrypt it again--all without writing any decrypted files to disk:

gpg --decrypt testfile2.asc | sed '$a\blah blah blah' | gpg --yes -ear omari@foo.com --output testfile2.asc

rahil khera · 02-28-2014, 09:41 AM

How to append in a file of type proc_fs. When my application calls the write function of proc file, it over-writes previous contents. I have tried O_APPEND, although it is working with normal file but not with the proc_fs file.