In a bash script/command how can I make a PC beep noise, or play a sound file?
This will make a beep from within bash echo -en “\007”
shell
How to run a script at the start up of Ubuntu? [closed]
First of all, the easiest way to run things at startup is to add them to the file /etc/rc.local. Another simple way is to use @reboot in your crontab. Read the cron manpage for details. However, if you want to do things properly, in addition to adding a script to /etc/init.d you need to tell … Read more
How to set environment variables from .env file
If your lines are valid, trusted shell but for the export command This requires appropriate shell quoting. It’s thus appropriate if you would have a line like foo=’bar baz’, but not if that same line would be written foo=bar baz set -a # automatically export all variables source .env set +a If your lines are … Read more
Docker compose won’t find $PWD environment variable
You don’t need ${PWD} for this, you can just make the path relative and compose will expand it (one major difference between compose paths and those processed by docker run). version: ‘2’ services: couchpotato: build: context: ./couchpotato dockerfile: Dockerfile ports: – 5050:5050 volumes: – “./couchpotato/data:/home/CouchPotato/data/” – “./couchpotato/config:/home/CouchPotato/config/” As for why compose doesn’t see this variable, … Read more
Shell script variable not empty (-z option)
Of course it does. After replacing the variable, it reads [ !-z ], which is not a valid [ command. Use double quotes, or [[. if [ ! -z “$errorstatus” ] if [[ ! -z $errorstatus ]]
What is the difference between $@ and $* in shell scripts?
From here: $@ behaves like $* except that when quoted the arguments are broken up properly if there are spaces in them. Take this script for example (taken from the linked answer): for var in “$@” do echo “$var” done Gives this: $ sh test.sh 1 2 ‘3 4’ 1 2 3 4 Now change … Read more
How do I extract the created date out of a Mongo ObjectID
getTimestamp() The function you need is this one, it’s included for you already in the shell: ObjectId.prototype.getTimestamp = function() { return new Date(parseInt(this.toString().slice(0,8), 16)*1000); } References Check out this section from the docs: Extract insertion times from _id rather than having a separate timestamp field This unit test also demostrates the same: mongo / jstests … Read more
unzip password protected zip in unix
unzip -P your-password zipfile.zip man unzip -P password use password to decrypt encrypted zipfile entries (if any). THIS IS INSECURE! Many multi-user operating systems provide ways for any user to see the current command line of any other user; even on stand-alone systems there is always the threat of over-the-shoulder peeking. Storing the plaintext password … Read more
How to remove trailing whitespaces for multiple files?
You want sed –in-place ‘s/[[:space:]]\+$//’ file That will delete all POSIX standard defined whitespace characters, including vertical tab and form feed. Also, it will only do a replacement if the trailing whitespace actually exists, unlike the other answers that use the zero or more matcher (*). –in-place is simply the long form of -i. I … Read more
Trim leading and trailing spaces from a string in awk
If you want to trim all spaces, only in lines that have a comma, and use awk, then the following will work for you: awk -F, ‘/,/{gsub(/ /, “”, $0); print} ‘ input.txt If you only want to remove spaces in the second column, change the expression to awk -F, ‘/,/{gsub(/ /, “”, $2); print$1″,”$2} … Read more