Navigating Shell for Productivity and Profit

Navigating Shell for Productivity and Profit

I hope you find inspirations from these pretty neat shell tricks and my shell setup.

Array Expansion

Use Array Expansion to quickly build arguments to a command. For example, to download several HTTP resources:

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$ wget https://kubernetespodcast.com/episodes/KPfGep{001..062}.mp3

To rename files when you just want to change a substring.

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$ mv /path/to/same-prefix-{old,new}.txt

Process Substitution and Anonymous Files

<() redirects the stdout of the command in the subshell to a file descriptor opened at /dev/fd. This is known as process substitution.

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$ sh <(curl -sL https://istio.io/downloadIstioctl)

The above is equivalent to the following, where - means to use the stdin as a file.

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$ curl -sL https://istio.io/downloadIstioctl | sh -

Note that process substitution is more powerful than pipes, since you can do things like

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$ diff <(ssh somehost cat /etc/hosts) <(ssh some-other-host cat /etc/hosts)

Start new shell

Just updated your bashrc/zshrc file, but want to hold on to your environment variables, file descriptors, etc? Do this.

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$ exec -l $SHELL

The password is sudo

Dealing with production outage and in dire need of mitigation?

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$ sudo su

And then you are always the root master. “I don’t test in prod; I dev in prod.”

Alias for the Win

Type less. Move fast. Here are some I use everyday.

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mcd() { mkdir -p "$1" && cd "$1" }
cdl() { cd "$1" &&  ls }

alias ls='ls -F -G'
alias ll='ls -lh'
alias o='open'
alias ping='ping -c 5'
alias gauth='gcloud auth login --update-adc'

(I consider it a work injury that I now quote everything in shell and has long stopped using white space in file names even for personal stuff. Maybe you are like me.)

Cursor Navigation

Ctrl-A and Ctrl-E jump to the command's start and end; Alt-B and Alt-F move backward and forward by a word.

Command Deletion

Ctrl-U deletes from the cursor to the line's start, Ctrl-K to its end, and Ctrl-W deletes the word before the cursor.

In-line file

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cat << EOF | kubectl create -f -
apiVersion: v1
kind: Pod
metadata:
name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
EOF

Search Command History with Fuzzy Find

You probably know you could use ctrl+r to retrieve a previously executed command quickly, but it only gives you one suggestion. fzf solves it not only for commands but finds files as well.

Typing grep in fzf filters command history to multiple matching commands, with one highlighted for selection.

Auto-correct Command Typos

I don’t endorse profanity but we all share the frustration. Thefuck will correct your mistake.

Running fuck after a failed command suggests a correction: aptget becomes apt-get, missing sudo is added, and git brnch and puthon are fixed.

ZSH, ohmyzsh, and powerlevel10k

ZSH, or Z shell, is an extended version of the Bourne Shell (sh), with numerous new features, plugins, and themes. To change your shell to ZSH

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$ chsh -s $(which zsh)

Ohmyzsh is a plugin manager for ZSH. I recommend at least two plugins.

autosuggestions makes zsh like fish.

After typing gcloud, zsh autosuggestions offers auth login in dim text to complete the command.

syntax-highlighting colorizes the command and strings, providing visual warning for typos.

Syntax highlighting marks touch as valid in green and the typo tuoch in red; running tuoch produces command not found.