* SedTool
* AwkTool
* PerlScripts

### Environment

#### printenv
```plaintext
printenv # prints environment variables received from parent process
printenv VARNAME # prints VARNAME
```


### Export
If a variable is not marked for export, it won't be received from the parent. `printenv` gives you a way to check what is being sent to subprocesses.
To export a variable, use
```plaintext
export VARNAME
```
and you can also assign at the same time
```plaintext
export VARNAME=value
```

### Date and time
```plaintext
date # prints date in human readable format
date +FORMAT # use FORMAT string (see manpage)
date +%s # print UNIX timestamp
TZ="Japan" date # print date and time in Japan
```

### Processes
```plaintext
ps # list processes
pgrep <pattern> | xargs ps # list processes whose names match <pattern>
```

#### Jobs
```plaintext
bg # run job in background
fg # run job in foreground 
jobs # print current jobs
kill # send signal to process
kill -9 # immediately terminate process (process cannot intercept)
kill -15 # tell process to terminate (process can intercept)
```

#### Key combos
```plaintext
Ctrl-z # send SIGSTOP to current foreground process
Ctrl-c # Interrupt/terminate current foreground process
Ctrl-\ # Abort and core dump current foreground process
```


### Find
```plaintext
find . -type f # find regular files
find . -type l # find symbolic links
find . -type d # find directories
find . -name \*x* # find files with an 'x' in their name (\* to avoid expansion)
find . -name \*x* -exec command params {} \; # execute command params filename for each file found
```