Oneliners

Some small, random but possibly useful snippets for various tasks for oblivious shell users

Miscellaneous

Output unique lines of a text file

cat diff.txt | sed "s/^[ \t]*//" | sort | uniq

Find content in file recursive

grep --include=*.sql -rnw . -e "pattern"

Concat the content of all alphabetically orderd txt files

find . -type f -name '*.txt' | sort | xargs cat 0 >> concat.txt

Find all filenames recursive and print them sorted

find . -exec ls -dl \{\} \; | awk '{print $9}' | sort    

Replace file content

sed -i -e 's/foo/bar/g' filename

Remove empty lines from file

sed -i '/^$/d' file.txt

Execute command in every subfolder

find . -maxdepth 1 -type d \( ! -name . \) -exec bash -c "cd '{}' && pwd" \;

Find all entities not in persistence.xml

egrep -lir --include=*.java "@Entity" . | awk -F"/" '{print $NF}' | awk -F"." '{print $1}' | while read -r file ; do     
    if ! grep -q "$file" src/main/resources/META-INF/persistence.xml ;
    then
    echo "Missing entity $file"
    fi
done    

Pulls all git repos in subdirectories

find . -type d -mindepth 1  -maxdepth 1 -exec git --git-dir={}/.git --work-tree=$PWD/{} pull origin master \;   

Image manipulation

Convert every JPG in current folder to PNG

for image in *.jpg ;  do magick "$image" "${image%.*}.png" ; done

Optimize every PNG in current folder

for image in *.png ;  do optipng "$image" ; done

System

Find process that is using a particular port

sudo netstat -lpn | grep :8080

Scan wifi channels

sudo iwlist wlan0 scan | grep \(Channel

List of packages installed locally

dpkg -l

List files from package(s).

dpkg -L <packagename>

Restart Pulse Audio

pulseaudio -k && sudo alsa force-reload

Docker

Remove all containers

docker rm $(docker ps -a -q)

Remove all images

docker rmi $(docker images -q)