Dammit Jim!

I managed to forget how to redirect standard input (when you want to feed a bunch of lines to a program) in a bash script while still indenting and had to go digging around for it. So I figured I’d make a note here so I don’t forget again and for anyone else in the same boat. It’s just <<- instead of <<. For example if you want to keep indentation within a loop:

[bash] for i in 1 2 3 4;do catYou can use whatever you want to indicate the end of the input instead of EOF if it floats your boat (as long as you use the same thing both times) but unfortunately <<- doesn’t work with spaces for indentation (although I’m a tab man myself).

This is pretty basic knowledge but I’ve helped a few people out recently that had been using Unix/Linux for a while and didn’t know and it sure helped me out when I figured it out. If you had asked me how many quotation marks were on a keyboard before I started doing Bash stuff I would have said two. But I, and it seems most non-programmers, often forget the little ` on the same key as the tilde ~ (to the left of the numbers on standard keyboards). So there are actually three types of quotation marks and each one means something different to Unix:

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I guess this is obvious to most people but it took me quite a while to dig it out on the internet. I wanted my bash script to be able to read from standard input like cat sourcefile.txt|bash myscript.bash. It turns out the standard input can be read from /dev/stdin. So if I wanted to sort the standard input, myscript.bash would look like: sort /dev/stdin

I think this is probably basic UNIX knowledge but I’m not a programmer.