Using command and variable substitution we can stack up small commands to do big jobs. Command substitution allows you to execute commands in the middle of text. Variable substitution allows you to insert variables into your commands.
- [Instructor] We can insert a variable into…a text string or command line and have…the variable value substituted for the variable name.…For instance, in a terminal type echo, space,…double quote, my space name, space, is, space,…dollar sign, capital USER, double quote and hit enter.…This outputs the text my name is…followed by the value and the user variable.…As we've seen elsewhere in this course,…we need to be careful with quoting.…
In order to have variable substitution,…we need to use double quotes.…This echo command is pretty basic.…Now let's use a command to process…the value of a variable.…To set this up, let's create a couple of variables.…In a terminal, type in PDIR equals double quote…slash TMP, slash files, slash today,…double quote and hit enter.…Let's create a second variable called fname.…Fname equals double quote, report, double quote.…
And hit enter.…Variable names can be uppercase or lowercase.…Most system variables are uppercase.…Now let's use these variables in a command.…Type in mkdir, space, dash P, space,…
- Write the command that will take you to the most recent directory.
- Write the command that brings back the arguments and options from the previous line.
- Explain what extended globs can do.
- Identify the access.conf line that will restrict all users from using the cron service except for the user named bob.
- List the line that will get a list of only running services.
- Identify what typing ‘systemctl enable crond’ will do.
Skill Level Intermediate
Linux: User and Group Managementwith Grant McWilliams1h 8m Intermediate
1. Linux Shells Overview
2. Using the Bash Shell
3. Linux Processes
4. Job Scheduling
5. System Services
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