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Thanks to this user: https://stackoverflow.com/a/35636373/2394635 Show Sample Output
1s='Test "checkin_resumestorevisit \"- "Online_V2.mt" Run'; s=${s#*'"'}; s=${s%'"'*}; echo "$s" -
Adding this alias to ~/.bashrc or, better yet, the system-wide /etc/bash.bashrc (as in my setup) will make it possible to not only run pacman as any user without needing to prepend sudo but will also ensure that it always assumes that the user knows what he or she is doing. Not the best thing for large multi-user enterprise setups at all to say the least, but for home (desktop) use, this is a fantastic time-saver.
3alias pacman=‘sudo pacman --noconfirm’ -
This is useful if you add sid, install some packages, then remove sid and want to work out which packages you installed from sid that should be removed (e.g. before an upgrade to the new stable). Alternatively you can think of this as "find installed packages that can no longer be installed."
1aptitude search -F '%p %v %V %O' '?narrow(?not(?archive("^[^n][^o].*$")),?version(CURRENT))' | while IFS=' ' read -r pkg ver candidate origin; do if [[ $ver == "$candidate" ]] && [[ $origin == '(installed locally)' ]]; then echo "$pkg"; fi; done -
Use lsbk (list block) and jq (to manipulate a JSON on the command line) to display partition information: Show Sample Output
2lsblk --json | jq -c '.blockdevices[]|[.name,.size]' -
It repeats a command, such as free, every five seconds and highlights the differences
1watch -n 5 -d '/bin/free -m' -
Sometimes things break. You can find the most recent errors using a combination of journalctl, along with the classic tools sort and uniq Show Sample Output
1journalctl --no-pager --since today --grep 'fail|error|fatal' --output json | jq '._EXE' | sort | uniq -c | sort --numeric --reverse --key 1 -
Raise your hand if you haven't used this at least once to share a directory quickly
3cd $mydir && python3 -m http.server 8888 -
The shell {} operator is great for this. Here's an example with three directories enclosed in {}:
0mkdir -p -v /home/user/tmp/{dir1,anotherdir,similardir} -
https://wuseman.nr1.nu:8080/file/E8AcLVgMPZ2LSJQf/9BD8V8ADYNhR6cca/parallel_print_progress.gif Show Sample Output
1seq 1000 |parallel -j30 --bar '(echo {};sleep 0.1)' -
Should run anywhere that Bash works.. Your mileage may vary. Show Sample Output
-2alias functions='shopt -s extdebug;declare -F | grep -v "declare -f _" | declare -F $(awk "{print $3}") | column -t;shopt -u extdebug' -
After downloading an ISO image, assuming you have QEMU installed, it’s possible to boot an ISO image in a virtual machine and then install that ISO from within the virtual machine directly to a physical drive, bypassing the need to reboot. Simply pass the ISO image as the -cdrom parameter, followed by “format=raw,file=/dev/sdb” (replace /dev/sdb with the drive you want to install to) as the hard drive parameter (making absolutely certain to specify the raw format, of course). Once you boot into the ISO image with QEMU, just run the installer as if it were a virtual machine — it’ll just use the physical device as an install target. After that, you’ll be able to seamlessly boot multiple distros (or even other operating systems) at once.
2sudo qemu-system-x86_64 -bios /usr/share/ovmf/x64/OVMF.fd -accel kvm -boot d -cdrom ubuntu-21.10-desktop-amd64.iso -drive format=raw,file=/dev/sdb -m 4096 -
Lists all installed kernels minus the current one. This is useful to uninstall older kernels that take too much space on /boot partition. Show Sample Output
4dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' -
This is a very hackish way to do it that I'm mainly just posting for fun, and I guess technically can more accurately be said to result in undefined behavior. What the command does is tell the shell to treat libpng like it's a shell plugin (which it's most certainly not) and attempt to install a "png_create_read" command from the library. It looks for the struct with the information about the command; since it's always the command name followed by "_struct", it'll look for a symbol called "png_create_read_struct". And it finds it, since this is the name of one of libpng's functions. But bash has no way to tell it's a function instead of a struct, so it goes ahead and parses the function's code as if it was command metadata. Inevitably, bash will attempt to dereference an invalid pointer or whatever, resulting in a segfault.
3enable -f /usr/lib/libpng.so png_create_read -
1until ssh login@10.0.0.1; do echo "Nope, keep trying!"; fi; sleep 10; done
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Useful when you wait for a server to boot up.
0while true; do ssh login@10.0.0.1; if [[ $? -ne 0 ]]; then echo "Nope, keep trying!"; fi; sleep 10; done -
4openssl s_client -showcerts -connect google.com:443 </dev/null 2>/dev/null|openssl x509 -outform PEM > /tmp/google.com.cer
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Since systemd-resolved was implemented, add a DNS server have become weirder and harder than before. With this command, you can add a DNS server on-the-fly tied to an specific interface
5sudo systemd-resolve --interface <NombreInterfaz> --set-dns <IPDNS> --set-domain mydomain.com -
Check if TCP port is reacheable Show Sample Output
2Test-NetConnection -ComputerName example.com -Port 443 -
2time seq 65535 | parallel -k --joblog portscan -j9 --pipe --cat -j200% -n9000 --tagstring '\033[30;3{=$_=++$::color%8=}m' 'nc -vz localhost $(head -n1 {})-$(tail -n1 {})'
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Clear Cached Memory on Ubuntu based distributions, and also display memory status. Please do not use this on a production machine unless you really really know what you are doing. Echo 3 is a kinder way of purging the memory, you can also use 'echo 2' or 'echo 1' if #1 You know what you are doing, and #2 refer to number 1 :-)
0sudo free && sync && sudo echo 3 | sudo tee /proc/sys/vm/drop_caches -
Useful for checking if a large number of PNG files was downloaded successfully by verifying the built-in CRC checksum. For incomplete files, the command will print: "00002309.png EOF while reading IDAT data ERROR: 00002309.png" The process is very fast; checking 21,000 files of 5MB in size took only five minutes on a 2011 Intel mobile dual-core.
1ls *.png |parallel --nice 19 --bar --will-cite "pngcheck -q {}" -
1bash -c 'exec 3<>/dev/tcp/google.com/80; echo EOF>&3; cat<&3'
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0openssl s_client -connect HOSTNAME.at:443 -showcerts </dev/null 2>/dev/null | openssl x509 -outform PEM > meinzertifikat.pem
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Read a file or standard input and only outputs lines that start with a dot or period "." Show Sample Output
0grep '^\.' file -
-1export IP="$(hostname -I | awk '{print $1}')"
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