CLI
When using sort the -h or the longopt version --human-numeric-sort sort human readable numbers (e.g., 2K 1G) du -hd1 | sort -h 321M ./.ccache 508M ./build-perl-squeeze 862M ./7.6.1 Add -r to sort to get the largest listed first.
CLI
BASH's history expansion character, ! has many features, including !: for choosing a specific argument (or range of arguments) from the history. The gist is any number after !: is the number of the argument you want, with !:1 being the first argument and !:0 being the command. echo one two three one
CLI
Lets explore a couple ways to get random numbers on the command line. > Anyone who attempts to generate random numbers by deterministic means is, of course, living in a state of sin. John von Neumann $RANDOM Bash Internal $RANDOM is an internal Bash function (not a constant) that returns a
CLI
This is an easy way to see what IP a website is seeing you come from: curl httpbin.org/ip { "origin": "52.11.93.181" } curl icanhazip.com 52.11.93.181 Lots of other options, but these are some of the shortest I've seen.
CLI
ps -p $$ PID TTY TIME CMD 76146 ttys002 0:54.05 -bash echo $SHELL /bin/bash The first gets the PID and command of the current shell, the second is an environment variable that should be set in most shells.
CLI
The function will take a string and create an MP3 of the string being spoken and named after the first 15 characters of the string: t2s() { wget -q -U Mozilla -O $(tr ' ' _ <<< "$1"| cut -b 1-15).mp3 "http://translate.google.com/translate_tts?ie=UTF-8&tl=en&q=
CLI
dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -n Similar the the RPM [https://xensoft.com/find-the-largest-installed-rpms/] equivalent. However, the above doesn't seem to always list the "Installed Size" - you can always fall back to this brute force method: dpkg --get-selections | cut -f1 | while read pkg; do dpkg -L
CLI
Note: If things are not working as described below check the version information for parallel. parallel --version WARNING: YOU ARE USING --tollef. IF THINGS ARE ACTING WEIRD USE --gnu. ... Either add --gnu to all your parallel commands, or edit /etc/parallel/config and make sure it lists --gnu and not
CLI
Need to tinker with an initrd.img or initramfs.img? Here are the steps to unpack these files and then put them back together again if you've made any changes. First step, make a copy of the initrd.img or initramfs.img in question: cp /boot/initramfs-*.img /tmp The
Bash
Basic Variable Usage * $VARIABLE * ${VARIABLE} BASH variables are case sensitive, e.g. $VARIABLE is not the same as $variable. The curly bracket syntax allows the variable name to be delimited from trailing characters that otherwise might be interpreted as part of the variable name: VARIABLE=end echo "The opposite of
MySQL
Backing up MySQL used to be quick, easy and silent using mysqldump, but more recent versions of MySQL produce the following nagging warning: mysqldump -u root -p --all-databases --single-transaction > bak.sql Enter password: -- Warning: Skipping the data of table mysql.event. Specify the --events option explicitly. If you'd like
MySQL
The following SQL will create a MySQL user with the minimum number of privileges necessary to backup databases: CREATE USER 'backup'@'localhost' IDENTIFIED BY '#PASSWORD#'; GRANT SELECT, RELOAD, FILE, SUPER, LOCK TABLES, SHOW VIEW ON *.* TO 'backup'@'localhost' IDENTIFIED BY '#PASSWORD#' WITH MAX_QUERIES_PER_HOUR