Please follow and complete the free online Command Line Crash Course tutorial. This is a great, quick tutorial. Each "chapter" focuses on a command. Type the commands you see in the Do This section, and read the You Learned This section. Move on to the next chapter. You should be able to go through these in a couple of hours.
###Q1. Cheat Sheet of Commands
Make a cheat sheet for yourself: a list of at least ten commands and what they do, focused on things that are new, interesting, or otherwise worth remembering.
- find [dir] -name [search_pattern]
- grep: stands for global regular expression print. It searches files for lines that match a pattern and returns the results. It is case sensitive.
- cd ../../
- .. (parent/enclosing directory)
- env: returns a list of environment variables
- touch: creates a new file inside the working directory. It takes in a file name as an argument and creates a new empty file in the current working directory.
- sed 's/he/she' file.txt: stands for "stream editor." It accepts standard input and modifies itbased on an expression expression before displaying it as output data. In the expression 's/he/she', s stands for "substitution," he is the search string, and she is the replacement string.
- rm -r directory_name: deletes a directory and all of its child directories
- mkdir directory_name: takes in a directory name as an argument and creates a new directory in the current working directory
- mv file.txt directory_name/: moves the file (first argument) into the destination directory (second argument)
###Q2. List Files in Unix
What do the following commands do:
ls: lists the files in a directory (short listing)
ls -a: lists all content in the working directory, including hidden files and directories
ls -l: long listing
ls -lh: long listing with Human readable file sizes
ls -lah: displays the long format listing, all files,
ls -t: listing sorted by modification time
ls -Glp: inhibit display of group information, append indicator to entries
###Q3. More List Files in Unix
Explore these other ls options and pick 5 of your favorites:
- -p: displays directories with /
- -R: displays subdirectories as well
- -1: displays each entry on a line
- -d: displays only directories
- -m: displays the names as a comma-separated list
###Q4. Xargs
What does xargs do? Give an example of how to use it.
The xargs command expects the input from stdin and executes over the input Example: find . -print | xargs grep -l wordtofind