Discussions: Lobsters, /r/commandline

Some useful “tricks” from my ~/.zshrc; full version here. Not all of this is “copy/paste ready” but it should give you some inspiration to build your own stuff :-)

General tip: I found the User’s Guide to ZSH very helpful when learning about zsh. It hasn’t been updated in a while and isn’t even finished, but found it’s quite well-written and useful. Go read it!

Directory shortcuts

Define directory shortcuts with hash -d so you can use cd ~x and vim ~x/file instead of cd /very/long/and/often/accessed/path. Some examples:

# Directory shortcuts
hash -d pack=$HOME/.cache/vim/pack/plugins/start
hash -d vim=/usr/share/vim/vim82
hash -d d=$HOME/code/arp242.net/_drafts
hash -d p=$HOME/code/arp242.net/_posts
hash -d go=/usr/lib/go/src
hash -d c=$HOME/code
hash -d gc=$HOME/code/goatcounter

So if I have an idea for a new post here I just type vi ~d/$(td)-idea.markdown and presto (td is alias td='echo $(date +%Y-%m-%d)').

If you put %~ in your PROMPT then the short version will show up there, too:

$ PROMPT='[%~]$ '
[~]$ cd ~/.cache/vim/pack/plugins/start
[~/.cache/vim/pack/plugins/start]$ hash -d pack=$HOME/.cache/vim/pack/plugins/start
[~pack]$

A related little helper I have is hashcwd, to quickly add the current directory in case you find yourself in a (very) long path taking up all your screen space or want to make a temporary “bookmark”:

hashcwd() { hash -d "$1"="$PWD" }

And then:

[~/go/pkg/mod/golang.org/x/tools@v0.0.0-20200519205726-57a9e4404bf7/go/analysis]$ hashcwd a
[~a]$ 

Filter history completion with what you typed

Make up and down arrow take what’s typed on the commandline in to account. E.g. if you type ls and press up it will only find history entries that start with ls:

autoload -Uz up-line-or-beginning-search down-line-or-beginning-search

zle -N up-line-or-beginning-search
zle -N down-line-or-beginning-search

bindkey '^[[A'  up-line-or-beginning-search    # Arrow up
bindkey '^[OA'  up-line-or-beginning-search
bindkey '^[[B'  down-line-or-beginning-search  # Arrow down
bindkey '^[OB'  down-line-or-beginning-search

I use this a lot, and is the #1 thing I miss if it’s not available.

You can also use history-incremental-search-backward to search the entire commandline, but I never cared for it much as ls will match alsamixer, tools, tls, totals, docker ls, and probably more.

Easier PATH

Many systems link /bin to /usr/bin and storing all of those in PATH isn’t too useful. Some helper functions to prepend or append to PATH which also check if the path exists so it’s easier to write a portable zshrc:

typeset -U path  # No duplicates
path=()

_prepath() {
    for dir in "$@"; do
        dir=${dir:A}
        [[ ! -d "$dir" ]] && return
        path=("$dir" $path[@])
    done
}
_postpath() {
    for dir in "$@"; do
        dir=${dir:A}
        [[ ! -d "$dir" ]] && return
        path=($path[@] "$dir")
    done
}

_prepath /bin /sbin /usr/bin /usr/sbin /usr/games
_prepath /usr/pkg/bin   /usr/pkg/sbin   # NetBSD
_prepath /usr/X11R6/bin /usr/X11R6/sbin # OpenBSD
_prepath /usr/local/bin /usr/local/sbin

_prepath "$HOME/go/bin"                # Go
_prepath "$HOME/.local/bin"            # My local stuff.
if [[ -d "$HOME/.gem/ruby" ]]; then    # Ruby
    for d in "$HOME/.gem/ruby/"*; do
        _postpath "$d/bin";
    done
fi

unfunction _prepath
unfunction _postpath

Easier alias

A little _exist helper to check if a binary exists is similarly useful for a portable zshrc:

_exists() { (( $+commands[$1] )) }

_exists vim      && export EDITOR=vim
_exists less     && export PAGER=less
_exists bsdtar   && alias tar='bsdtar'
_exists htop     && alias top='htop'

if _exists vim; then
    alias vim="vim -p"
    alias vi="vim"
fi

unfunction _exists

Edit ag and grep results

“ag edit” and “grep edit” to quickly open stuff found with ag or grep in Vim:

# "ag edit" and "grep edit".
age() {
    vim \
        +'/\v'"${1/\//\\/}" \
        +':silent tabdo :1 | normal! n' \
        +':tabfirst' \
        -p $(ag "$@" | cut -d: -f1 | sort -u)
}
grepe() {
    vim \
        +'/\v'"${1/\//\\/}" \
        +':silent tabdo :1 | normal! n' \
        +':tabfirst' \
        -p $(grep "$@" | cut -d: -f1 | sort -u)
}

$ ag pattern
[.. check if results look right ..]

$ age pattern
[open in Vim]

This will also search for the pattern with /pattern in Vim and move to the first match for every tab (yes, I use Vim tabs, in spite of Vim-purist philosophy that they’re bad).

Caveat: the Vim regexp syntax isn’t quite the same as extended POSIX or PCRE, so the pattern doesn’t always work as expect in Vim. It works most of the time though.

Caveat 2: sometimes I use this to check if I have the expected results:

$ ag pattern | less

And then I modify it age while forgetting to remove the less:

$ age pattern | less

Vim will not like this 😅 Not sure if we can write something to be a bit smarter about this. Ideally I would be smarter, but alas I am not.

Global aliases

You can define global aliases with alias -g, which will work everywhere. I use it to make piping stdout and stderr to less or Vim a bit easier:

alias -g VV=' |& vim -'
alias -g LL=' |& less'

$ ls LL
$ go test -v VV

Bonus Vim tip: convert a buffer to “scratch” with:

" Convert buffer to and from scratch.
command S
    \  if &buftype is# 'nofile' | setl swapfile buftype= bufhidden=
    \| else                     | setl noswapfile buftype=nofile bufhidden=hide | endif
    \| echo printf('swapfile=%s buftype=%s bufhidden=%s', &swapfile, &buftype, &bufhidden)

And then use:

alias -g VV=' |& vim +S -'

Use :S from Vim to make it a regular buffer again.

Playground environment

Set up a quick “tmp go” environment for testing; I mostly use Go these days, but this can be done for other languages as well:

tgo() {
    tmp="$(mktemp -p /tmp -d "tgo_$(date +%Y%m%d)_XXXXXXXX")"
    printf 'package main\n\nfunc main() {\n\n}\n' > "$tmp/main.go"
    printf 'package main\n\nfunc TestMain(t *testing.T) {\n\n}\n\n' > "$tmp/main_test.go"
    printf 'func BenchmarkMain(b *testing.B) {\n\tb.ReportAllocs()\n\tfor n := 0; n < b.N; n++ {\n\t}\n}\n' >> "$tmp/main_test.go"

    printf 'module %s\n' "$(basename "$tmp")" > "$tmp/go.mod"
    (
        cd "$tmp"
        vim -p main.go main_test.go
        echo "$tmp"
    )
}

It will create a main.go and main_test.go in /tmp/ with some useful boilerplate and a go.mod so it’s recognized as a module (required to get gopls etc. to work well) and opens the whole shebang in Vim.

This won’t be removed after Vim exits on purpose, so you won’t lose your prototype.

Run stored SQL queries

I have a bunch of scripts in ~/docs/sql/scripts to get some stats and whatnot from PostgreSQL. This adds a sql command with tab-completion to that directory and runs psql with some useful flags:

sql() {
    cmd="psql -X -P linestyle=unicode -P null=NULL goatcounter"
    f="$HOME/docs/sql/scripts/$1"
    if [[ -f "$f" ]]; then
        eval "$cmd" < "$HOME/docs/sql/scripts/$1" | less -S
    else
        eval "$cmd" <<< "$1" | less -S
    fi
}
_sql() { _files -W ~/docs/sql/scripts }
compdef _sql sql

If the file doesn’t exist then the query is just run:

$ sql ls-inactive.sql

$ sql 'select * from sites'

less -S prevents wrapping long lines, which I find more useful for tabular output.

Shortcuts to edit commandline

Custom mappings to preform some common substitutions, use <C-r> to prepend doas to the commandline, or <C-r> to replace the first word with rm:

insert_doas() { zle beginning-of-line; zle -U "doas " }
replace_rm()  { zle beginning-of-line; zle delete-word; zle -U "rm " }

zle -N insert-doas insert_doas
zle -N replace-rm replace_rm

bindkey '^s'    insert-doas
bindkey '^r'    replace-rm