Bash cheatsheet

Bash commands that have proven to be very useful for me

Working with the file system

Find folders and files in the file system

# finding all files (-type f) with name starting with 'sidekiq' (-name "sidekiq*")
find /path/to/folder -type f -name "sidekiq*"

Taking each files in a directory and doing something with them

# Printing all files in a directory
ls . | while read i; do echo $i; done

Remove files with specific extension in all subdirectories

# To list all *.pyc files
find . -name "*.pyc" -type f

# To delete all *.pyc files
find . -name "*.pyc" -type f -delete

Find and replace text within a file

# To update the input file
sed -i 's/text_to_find/replace_text/g' input_file.txt

# To create a new file  with the changes
sed 's/text_to_find/replace_text/g' input_file.txt > output_file.txt

# case-insensitive
sed -i 's/text_to_find/replace_text/gI' input_file.txt

# Replacing commas by dots in floats
sed -i -r 's/([0-9]),([0-9])/\1.\2/g' input_file.txt

Find text in files

# Find files containing specific text
grep -iRl 'text_to_find' directory

# -i - ignore text case
# -R - recursively search files in subdirectories.
# -l - show file names instead of file contents portions.
# -n - prints the line numbers

# Find sepcific text within a file
grep -i 'text_to_find' input_file.txt
grep 'text_to_find' input_file.txt  # Case sensitive

Print n lines of a file

# Print the first 20 line of a file
sed -n 1,10p input_file.txt

Displaying path of the current directory

pwd

Using Tar command to compress and extract files

tar -czvf name-of-archive.tar.gz /path/to/directory-or-file  # compressing
tar -xzvf name-of-archive.tar.gz  # extracting

Downloading and transfering files

Transfer files (scp)

# Copy single file from local to remote
scp myfile.txt remoteuser@remoteserver:/remote/directory/

# Copy single file from remote to local
scp remoteuser@remoteserver:/remote/directory/myfile.txt  myfile.txt

Download a file

wget http://example.com/file

Downloading an http server directory

# from https://superuser.com/questions/655554/download-all-folders-subfolders-and-files-using-wget

wget -r --no-parent http://www.mysite.com/Pictures/

# Tto retrieve the content, without downloading the "index.html" files:
wget -r --no-parent --reject "index.html*" http://www.mysite.com/Pictures/

Knowing the file lenght before download it

wget http://example.com/file --spider --server-response -O - 2>&1 | sed -ne '/Content-Length/{s/.*: //;p}'

Installing packages (Ubuntu)

Installing subversion

# Install Apache subversion client and server
sudo apt-get install subversion

# Install RabbitVCS
sudo apt-get install rabbitvcs-cli rabbitvcs-core rabbitvcs-gedit rabbitvcs-nautilus

Installing temperature monitors

# Installing sensors
sudo apt install lm-sensors hddtemp
sudo sensors-detect
sensors
sudo apt install psensor

Uncategorized

making a bootable usb drive by simply mounting an image

# listing block devices
lsblk

# if: file to load the image from
# of: partition to mount the image in
sudo dd if=/path/to/linux/distro/iso/image/file.iso of=/dev/sdb1 

Convert a classic image to an eps image

convert mainview.png eps2:mainview.eps

Convert EPUB to PDF

# Installing calibre
sudo apt-get -y install calibre

# Converting
ebook-convert <file>.epub <file>.pdf