bashoneliners.com

Explanation

Amazon Web Services (AWS) use a collection "IAM" resources to create Users and related objects in the system. This oneliner scrapes all the relevant info and puts it into Terraform. This lets us audit our users-groups. And, it lets us re-use them in another environment!

Explanation

1. First makes directory for portraits and landscapes
2. Loops through all files in the current directory with the extention .jpg, feel free to change this to .png or .jpeg if neccesary
   1. Gets the width and height for the current image using the identify command
   2. If height > width, move it to Portarits folder, otherwise move it to landscapes

Explanation

for loop will go trough every file that is finished with ".full" split that in file in files of 100000 rows. Rename the first one as input name but deleting the extension and adding ".txt" as extension. As last stem it will delete the rest of split files.

Explanation

Combines ps, lsof, and sort in the ways you might expect to produce the intended outcome.

Explanation

docker ps -a -f network=$NETWORK --format='{{.ID}}' returns the id's of all container that are subscribed to the network and pass the output to xargs docker rm -f that stop and deletes each container

Explanation

Supposing that you are in a directory that contains many subdirectories with a docker-compose file each one and instead of up one by one manually you want run all at time, well this is a helpful command for this purpose

Explanation

This command search for files that contain and an specific string and then find a pattern on those files and replace it

Explanation

One json object provided by puppet dictionary the other grabbed from Elasticsearch rest API. Only run command if these don't match. Had issues getting jq to sort properly so used python.

Explanation

• iw dev IFACE scan get info about scanned APs
• egrep "SSID|signal" take only name and signal
• awk -F ":" '{print $2}' cut labels of fields
• sed 'N;s/\n/:/' join couples to single line
• sort sort by signal asc

IFACE - wifi interface (like wlan0)

Explanation

As before, we're using lsof to find the PID of the process running on port 8080. We use awk to store the second column of each line into a variable l, overwriting it with each line. In the END clause, we're left with the second column of only the last line. xargs passes that as a parameter to the kill command.

The only notable diffirence from the command listed above is the use of awk to also complete the tail -n 1 step. This awk pattern matches the same intended behavior of the script that was using tail. To kill all processes on that port, you could use the NR>1 clause instead of the variable loop.

Explanation

It does not return a failing exit code if there are no images removed. It should always succeed unless there was an actual problem removing a Docker image.

Explanation

This line :) searches values taken from a file (values_to_search.txt) by scanning a full file values list . If value found, it is added on a new file exit_FOUND.txt.

Alternatively, we can search for values from the list 1 which does NOT exists on the list 2, as bellow:

for ITEM in cat values_to_search.txt; do (egrep $ITEM full_values_list.txt || echo $ITEM not found) | grep "not found">> exit_not_found.txt; done

Explanation

docker images outputs all images currently available. By specifying -f "dangling=true" we restrict the list to "dangling" images (i.e. untagged). By specifying the -q option we use quiet mode, which limits the output to the images hash, which is the directly fed into docker rmi, which removes the images with the corresponding hashes.

Explanation

• We begin by testing if the script is not in a terminal with tty.
• If it is not we start a terminal that runs tty and saves it to a filename. $$ was set by the original script and is its PID. That is opened in the background using & and then the original script waits for the filename to appear, then reads and removes it.
• Finally, the main command is a special syntax of the bash builtin command exec that contains nothing but redirections (of stdout, stderr, and stdin) so they will apply to every command in the rest of the script file.

Explanation

post-list.csv contains list of URLs in my example.

• split -l 30 Split by 30 lines

• - Use stdin as input for split

• --filter Couldn't find a way to easily pipe to stdout from split, hence --filter

• jq -R . From the jq manual - Don’t parse the input as JSON. Instead, each line of text is passed to the filter as a string

• jq --slurp -c . From the jq manual - Instead of running the filter for each JSON object in the input, read the entire input stream into a large array and run the filter just once. -c makes it easier to pipe and use it in the xargs that follows.

• xargs -d "\n" -I % sh -c Execute a command for each array. Use "\n" as delimiter. Use % as a placeholder in the command that follows.

• Single quotes inside sh -c ' ... ' are escaped as '"'"' single-double-single-double-single. You can do whatever you need to inside sh -c ' ... && sleep 123'

Explanation

The jar command allows you to read or manipulate JAR (Java ARchive) files, which are ZIP files that usually contain classfiles (Java compiled bytecode files) and possibly manifests and configuration files. We specify that we want to list file contents (t) that we provide as an argument (f, otherwise the jar will be read from stdin).

From the output, we get only the paths that contain a classfile (grep), then the path to the package that contains it (xargs dirname), we get the unique, sorted paths and translate /s to .s (to display their names as they would be shown in Java syntax).

Explanation

Originally published (by me) on unix.stackexchange.com.

comm is a utility that compares sorted lines in two files. It outputs three columns: lines that appear only in the first file, lines that only appear in the second one and common lines. By specifying -23 we suppress the latter columns and only keep the first one. We can use this to obtain the difference of two sets, expressed as a sequence of text lines. I learned about comm here.

The first file is the range of ports that we can select from. seq produces a sorted sequence of numbers from $FROM to $TO. The result is piped to comm as the first file using process substitution.

The second file is the sorted list of ports, that we obtain by calling the ss command (with -t meaning TCP ports, -a meaning all - established and listening - and -n numeric - don't try to resolve, say, 22 to ssh). We then pick only the fourth column with awk, which contains the local address and port. We use cut to split address and port with the : delimiter and keep only the latter (-f2). ss also output an header, that we get rid of by grepping for non-empty sequences of numbers that are no longer than 5. We then comply with comm's requirement by sorting numerically (-n) and getting rid of duplicates with uniq.

Now we have a sorted list of open ports, that we can shuffle to then grab the first "$HOWMANY" ones with head -n.

Example

Grab the three random open ports in the private range (49152-65535)

comm -23 <(seq 49152 65535) <(ss -tan | awk '{print $4}' | cut -d':' -f2 | grep "[0-9]\{1,5\}" | sort | uniq) | shuf | head -n 3

could return for example

54930
57937
51399

Notes

• switch -t with -u in ss to get free UDP ports instead.
• drop shuf if you're not interested in grabbing a random port

Explanation

Source LIB only if the corresponding variable is not defined, in order to prevent circular reference loop in case of the same script has been sourced before during the sourcing event.

Explanation

The test_statement is under a child process (a.k.a. subshell), which will return a boolean output. The then_statement depends on the former to be executed. Otherwise, it will be done upon the latter.

Explanation

Will return excuting script's current working directory, wherever Bash executes the script containing this line.

Explanation

This will commit a message pulled from What the Commit.

-m allows you to provide the commit message without entering your editor

w3m is a terminal based web browser. We basically use it to strip out all of the html tags

head -n 1 will grab only the first line

Explanation

It creates dnsmasq-ru-blackhole.conf file with one line to route all domains of ru zone to 0.0.0.0.

You might use "address=/home.lab/127.0.0.1" to point allpossiblesubdomains.home.lab to your localhost or some other IP in a cloud.

Explanation

This will search all files and folders in the current directory for any with a new line character in them and remove the new line out of the file/folder.

Explanation

We take the output of journalctl since the last boot (-b flag) and output from PROTO= until the EOL. Then, we remove identification tags (PROTO=/SPT=/DPT=/LEN=) and print just the protocol and destination port (cols 1 and 3). We sort the output properly so we can aggregate them on the call over uniq.

Explanation

lsof lists open files (ls-o-f, get it?). lsof -i :8080 lists open files on address ending in :8080. The output looks like this

COMMAND  PID     USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
chrome  2619 qymspace  149u  IPv4  71595      0t0  TCP localhost:53878->localhost:http-alt (CLOSE_WAIT)`

We use awk 'NR > 1 {print $2}' to print the second column for lines except the first. The result is a list of PIDs, which we pipe to xargs kill to kill.