This content originally appeared on Stefan Judis Web Development and was authored by Stefan Judis
Today I came across this tweet by Safia Abdalla. It showed that you can use the cat
command to quickly add content to a file (cat - >> foo.txt
). The way it works is that you can directly write to stdin
until you hit ^D
or ^C
.
So I opened the manual for the cat
command and wanted to see what else is in there. One sentence suprised me though.
If file is a single dash (`-') or absent, cat reads from the standard input.
You can make the snippet even shorter! ?
$ cat - >> foo.txt
# is the same as
$ cat >> bar.txt
That's cool!
I also discovered that you can use cat
and stdin
right in between files and concat them (you have to use ^D
– ^C
doesn't work then). ?
$ cat 1.txt - 3.txt > all.txt
I'm not sure if I'll ever need this functionality but it's always good to know some shell tricks. Safia shares a lot more CLI tricks so you should definitely check these out.
Reply to Stefan
This content originally appeared on Stefan Judis Web Development and was authored by Stefan Judis
Stefan Judis | Sciencx (2017-07-24T22:00:00+00:00) The power of cat and stdin (#tilPost). Retrieved from https://www.scien.cx/2017/07/24/the-power-of-cat-and-stdin-tilpost/
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