# Shell-Oneliner

Based on https://github.com/onceupon/Bash-Oneliner
but mainly for ZSH, my personal needs and configuration.


## Terminal Tricks

```
Ctrl + r : begins a backward search through command history.(keep pressing Ctrl + r to move backward)
Ctrl + a : move to the beginning of line.
Ctrl + e : move to the end of line.
Ctrl + w : cut the word before the cursor; then Ctrl + y paste it
Ctrl + u : cut the line; then Ctrl + y paste it
Ctrl + x + Ctrl + e : launch editor defined by $EDITOR to input your command. Useful for multi-line commands.

Esc + c : converts letter under the cursor to uppercase, rest of the word to lowercase.
```

### ... with my own configuration

```
Ctrl + t : print current date
```

###  environment variables

```
$0   : name of shell or shell script.
$1, $2, $3, ... : positional parameters.
$#   : number of positional parameters.
$?   : most recent foreground pipeline exit status.
$-   : current options set for the shell.
$$   : pid of the current shell (not subshell).
$!   : is the PID of the most recent background command.

$USER     : current username
$HOSTNAME : current hostname
```

### length of variable

```
var="some string"
echo ${#var}
# 11
```

### replace

```
foo=tachchen
echo ${foo/a/-}
# t-chchen                                                                                                                        /0,0s
echo ${foo//c/-}
# ta-h-hen
```

## Math

### prime factors

```
factor 50
# 50: 2 5 5
```

## Sed

```
sed 1d filename         # remove first line
sed 1,100d filename     # remove line 1-100
```