Linux Terminal Tricks

Some things I found useful when using Linux terminal.

tmux is a must when working with limited screen or terminals. A great tmux-guide.

Execution Control¶

Command -	- Description
`Enter`	causes the current command line to be accepted
	Cursor location within the line does not matter
	If the line is not empty, it is added to the command history
`Esc`	Meta-prefix. If the Alt key is unavailable, the Esc key can be used in its place
`Ctrl-g`	Abort the current editing command
`Ctrl-_`	Incrementally undo changes to the line
`Alt-r`	Revert all changes to the line
`Ctrl-l`	Clear the screen
`Ctrl-c`	interrupt current execution
`Ctrl-r`	back-ward search commands saved in history

Editing Control

Command -	- Description
`Alt-f / Alt-rightkey`	move forward one word
`Alt-b / Alt-leftkey`	move backward one word
`Ctrl-a`	move to beginning of the line
`Ctrl-e`	move to end of the line
`Ctrl-u`	delete chars up to the beginning of the line
`Ctrl-k`	delete chars up to the ending of the line

Text Transformation

Command -	- Description
`Alt-u`	Change the current word to uppercase.
`Alt-l`	Change the current word to lowercase.
`Alt-c`	Capitalize the current word.
`Alt-t`	Transpose words. Exchange the word at the point with the word preceding it.
`Alt-.`	recall the last argument from the previous command's argument list

Beautify Terminal Outlook¶

Modify the ~/.bashrc to set a preferred terminal style.

The $PS1 bash env var represents the primary prompt string which is displayed when the shell is ready to read a command.

It takes the form of PS1="[\u@\H \W] \$ "

Find the full documentation of supported special chars in man bash, at the section PROMPTING. Here are some of them that is frequently used:

Char -	- Description
`\u`	username of current user
`\h`	hostname up to the first dot in this machine's domain name
`\H`	display the Full Qualified Domain Name (FQDN)
`\W`	basename of current working directory
`\$`	if root display '#', else display '$'
`\!`	display the history number of current command
`\D{<date-format>}`	add formatted time of current timestamp

You can change 3 aspects of the terminal outlook:

Text Format -	- Text color -	- Text-background color
0: normal text	30: black	40: black
1: bold	31: red	41: red
4: underlined	32: green	42: green
	33: yellow	43: yellow
	34: blue	44: blue
	35: purple	45: purple
	36: cyan	46: cyan
	37: white	47: white

To modify the text with the styles, use a format of \e[<bg-color>;<format>;<txt-color>m

If you need to change multiple parts of the prompt to use different styles, then use multiple \e[;;m followed by the parts.

PS1="\e[41;4;33m[\u@\h \W] \$ "

Rename file without typing the full path twice: mv /path/to/file{,.bak} the special syntax {,.bak} tells shell to repeat the full string with two substrings, one is empty and the other is .bak, which is the same as doing mv /path/to/file /path/to/file.bak

Useful aliases¶

# colorize/prettify some commands output
alias diff='colordiff' # (need to install colordiff)
alias egrep='egrep --color=auto'
alias fgrep='fgrep --color=auto'
alias grep='grep --color=auto'
alias ls='ls --color=auto'
alias ct='column -t'
alias dfc='df -hPT | column -t'
alias mountc='mount | column -t'

# quick cd
alias ..='cd ..'
alias 2..='cd ../../'
alias 3..='cd ../../../'
alias 4..='cd ../../../../'
alias ...='cd ../../../'
alias ....='cd ../../../../'

# quick clipboard (need to install xclip)
alias setclip="xclip -selection c"
alias getclip="xclip -selection c -o"

# datetime
alias d='date +%F'
alias t='date +%T'
alias dt='date +"%F %T"'
alias now='date +"[%F %T]"'

# k8s alias
alias kv='kubectl version'
alias getcontexts='kubectl config get-contexts'
alias usecontext='kubectl config use-context'
alias setnamespace='kubectl config set-context --current --namespace='
alias getpo='kubectl get pods'
alias getdep='kubectl get deployments'
alias getsvc='kubectl get services'
alias getrs='kubectl get replicasets'
alias execit='kubectl exec -it'
alias despo='kubectl describe pod'
alias desdep='kubectl describe deployment'
alias logs='kubectl logs'