cht.sh Command Tool
In Linux it can be hard to remember some commands or options and there is a great tool for that. cht.sh
For example :
vagrant@ubuntu-focal:~$ curl cht.sh/cat
cheat.sheets:cat
# POSIX way in which to cat(1); see cat(1posix).
cat -u [FILE_1 [FILE_2] ...]
# Output a file, expanding any escape sequences (default). Using this short
# one-liner let's you view the boot log how it was show at boot-time.
cat /var/log/boot.log
# This is an ever-popular useless use of cat.
cat /etc/passwd | grep '^root'
# The sane way:
grep '^root' /etc/passwd
# If in bash(1), this is often (but not always) a useless use of cat(1).
Buffer=`cat /etc/passwd`
# The sane way:
Buffer=`< /etc/passwd`
cheat:cat
# To display the contents of a file:
cat <file>
# To display file contents with line numbers
cat -n <file>
# To display file contents with line numbers (blank lines excluded)
cat -b <file>
tldr:cat
# cat
# Print and concatenate files.
# More information: <https://www.gnu.org/software/coreutils/cat>.
# Print the contents of a file to the standard output:
cat path/to/file
# Concatenate several files into an output file:
cat path/to/file1 path/to/file2 ... > path/to/output_file
# Append several files to an output file:
cat path/to/file1 path/to/file2 ... >> path/to/output_file
# Copy the contents of a file into an output file without buffering:
cat -u /dev/tty12 > /dev/tty13
# Write `stdin` to a file:
cat - > path/to/file
You may say, why do you need this when you already have the man command in Linux? The most important feature that makes cht.sh different is that it explains each option in the simplest and most simple way. It does not require installation.
Here are a few more examples :
vagrant@ubuntu-focal:~$ curl cht.sh/tail
cheat:tail
# To show the last 10 lines of <file>:
tail <file>
# To show the last <number> lines of <file>:
tail -n <number> <file>
# To show the last lines of <file> starting with <number>:
tail -n +<number> <file>
# To show the last <number> bytes of <file>:
tail -c <number> <file>
# To show the last 10 lines of <file> and to wait for <file> to grow:
tail -f <file>
tldr:tail
# tail
# Display the last part of a file.
# See also: `head`.
# More information: <https://www.gnu.org/software/coreutils/tail>.
# Show last 'count' lines in file:
tail --lines count path/to/file
# Print a file from a specific line number:
tail --lines +count path/to/file
# Print a specific count of bytes from the end of a given file:
tail --bytes count path/to/file
# Print the last lines of a given file and keep reading file until `Ctrl + C`:
tail --follow path/to/file
# Keep reading file until `Ctrl + C`, even if the file is inaccessible:
tail --retry --follow path/to/file
# Show last 'num' lines in 'file' and refresh every 'n' seconds:
tail --lines count --sleep-interval seconds --follow path/to/file
vagrant@ubuntu-focal:~$ curl cht.sh/touch
cheat:touch
# To change a file's modification time:
touch -d <time> <file>
touch -d 12am <file>
touch -d "yesterday 6am" <file>
touch -d "2 days ago 10:00" <file>
touch -d "tomorrow 04:00" <file>
# To put the timestamp of a file on another:
touch -r <refrence-file> <target-file>
tldr:touch
# touch
# Create files and set access/modification times.
# More information: <https://manned.org/man/freebsd-13.1/touch>.
# Create specific files:
touch path/to/file1 path/to/file2 ...
# Set the file [a]ccess or [m]odification times to the current one and don't [c]reate file if it doesn't exist:
touch -c -a|m path/to/file1 path/to/file2 ...
# Set the file [t]ime to a specific value and don't [c]reate file if it doesn't exist:
touch -c -t YYYYMMDDHHMM.SS path/to/file1 path/to/file2 ...
# Set the file time of a specific file to the time of anothe[r] file and don't [c]reate file if it doesn't exist:
touch -c -r ~/.emacs path/to/file1 path/to/file2 ...