Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ask HN: How can I get better at bash?

news.ycombinator.com

Post reply on HN
Print view View original

81–90 of 195 posts

Re: Ask HN: How can I get better at bash?

#81

Post by LinuxBender »

Sean1708 wrote: post #66
ikeyany wrote: post #55

Earlier quoted context omitted.

> Like iterating over the files in a directory, for example. If you think that's easy in Bash you have either have a funny definition of easy Maybe I'm overlooking something...but why wouldn't this work: for file in $(ls); do { }; done

$ mkdir "hi there" $ mkdir "how are you" $ ls -l total 8 drwxr-xr-x 2 xxxxxxxx xxxx 4096 Jun 26 14:54 hi there drwxr-xr-x 2 xxxxxxxx xxxx 4096 Jun 26 14:54 how are you $ for f in $(ls); do echo $f; done hi there how are you

You can use

  find . -type d
or set IFS.

  IFS='
  '

  or

  IFS='\n'
then reset it later. Perhaps store existing IFS in a variable so you can put it back. The \n vs actual line feed has to do with an edge case in cygwin and dos files.

Re: Ask HN: How can I get better at bash?

#82

Post by tehwalrus »

Set your default shell to bash, and every time something annoys you, look up how to fix it (stack overflow is basically complete at this point, if you know what to search for) and put it in your dotfiles.

I used to rely on fish, but after a couple of bugs (either in fish or my fingers, not sure) I switched back to bash at my job (on a Linux desktop).

After a few months I had built up a good set of aliases and functions (my most used function is rgrep, see below) and was confidently ^R reverse searching and so on. These things are great because as you jump systems (e.g. to macOS) they continue to work.

TLDR: Practise practise practise!

    # the rgrep function
    
    # recursive text file search from the current directory.
    function rgrep {
        if [ -z "$1" ];
        then
            echo "please supply a search string."
            return 1
        fi
        grep -rn $1 .
    }

Re: Ask HN: How can I get better at bash?

#83

Post by brad0 »

Don't listen to the guys who are saying not to learn bash. In the right circumstance bash is much better than any verbose python script.

I'd say learn the following topics:

pipe grep sed awk find

Once you feel comfortable using and combining these tools you should be able to find out the rest by yourself.

Re: Ask HN: How can I get better at bash?

#84

Post by jdreaver »

felixschl wrote: post #68

Read the manual front to back and install shellcheck. Doing both things has paid off for me a thousand times over. The rest is practice. Complete the bash exercises on Hackerrank. Bash is fantastic in it's domain but it does require serious study in my experience

I can second the shellcheck recommendation. Shellcheck makes great recommendations, and every suggestion has a corresponding code you can google to get to a detailed explanation of why that is considered a warning or error. Hell, even if I just considered the times I forgot to put quotes around a variable and got warned by shellcheck I would be happy that I use it.

Re: Ask HN: How can I get better at bash?

#85

Post by seorphates »

Most of the responses here so far that do not include some sort of a guide are not the responses you're looking for (imho).

Mind your pipes and quotes. Guard your variables with braces. Do not export everything, test for and (try to) handle return codes and conditions and keep it simple (emphasis simple) but most of all just write it.

BASH (or Bourne) is ubiquitous when dealing with systems (vs programs). You don't need to be on the fashionable lang of the day by any measure. BASH, for most cases, will always be there, always ready and, in most cases, is the default human interface for deployed systems. As scripting languages go you don't need "better", you need dependability, zero dependencies with no requirement for modules or any other whizbangwoohoo plug-in. Language Fashionistas and personal preferences aside at least some level of fluency with BASH should be mandatory for anyone interfacing with a system.

Re: Ask HN: How can I get better at bash?

#86

Post by boona »

I'm not sure if this answers your question since I'm not sure what the implications of your workflow are, but I got a huge jump in productivity with Oh My Zsh. It has a bunch of features like tab completing past commands, it includes various shortcuts, etc. It's also compatible with bash.

Re: Ask HN: How can I get better at bash?

#87

Post by raboukhalil »

A while back, I wrote a quick Bash guide called "Adventures in Data Science with Bash" (https://gumroad.com/l/datascience).

It covers basic Bash commands (head, less, grep, cut, sort, uniq, curl, awk, join), but also pipes, for loops, variables, arrays, and command substitution.

Re: Ask HN: How can I get better at bash?

#88

Post by psychometry »

Give up? Seriously.

I used to force myself to do all of my ad-hoc scripting in bash, but I got sick of the clunky way of parsing arguments, dealing with arrays, looping over data objects, etc.

I got pretty good at it, but at some point I decided just to stick to a language I knew well (R) to string together various pipelines and construct commands. Any high-level language would work, though. I'm much more productive now.

Re: Ask HN: How can I get better at bash?

#89

Post by kingmanaz »

Some suggestions:

Direct your focus to plain Bourne sh as much as possible, moving on only after you understand what enhancements over vanilla sh Korn or Bourne-Again actually offer.

Pick up Manis, Schaffer, and Jorgensen's "UNIX Relational Database Management" and work through the examples to get a feel for the philosophy behind large, complex applications written in shell.

Join a Unix community (sdf.org) and try to do useful things with shell (e.g. cron-schedule stock quote e-mail notifications via shell scripts, etc).

Re: Ask HN: How can I get better at bash?

#90

Post by peterwwillis »

From a 14+ year Linux/Unix admin:

Get a very brief reference book of every common UNIX command. Read all the commands, what they do, what options they take. Start using them.

Shells are most useful when they are used to tie together other programs. In order to do this, you have to know what all the command-line tools you have at your disposal are. Learn the tools, then start writing examples using them. Keep the examples and the docs somewhere to reference them later.

For quick reference, the command 'whatis' will give a blurb from the top of the command's man page. `whatis ls' "ls (1) - list directory contents". View many at once with "(cd /usr/bin; whatis * | grep -v noth)". Many often-used commands come in "util-linux" and "coreutils" packages. Read man pages completely when convenient.

It may also help to have a VM or desktop which has no GUI, where you will be forced to use the command-line. When I was starting out I used a desktop with no X server for months. You can get a lot more done than you think (and 'links -g' provides a graphical browser if you need images)

To learn more about Bash itself, you can look for server installation software packages made with Bash, or in the "init" tools distributed with big distros like RedHat, SuSE, etc before they used systemd. But it's better to get used to more shell-agnostic scripting using UNIX commands than it is to use Shell-specific language/syntax.

Post reply on HN