Is the shell’s `source` POSIX-standard?
It’s there under “dot”. NAME dot – execute commands in the current environment SYNOPSIS . file [etc.]
shell
How to export multiple variables with same value in ksh?
Ksh93 (or bash) doesn’t have such expressions, so it’s better to make it explicit. But you can bundle multiple variables (with their initial values) in a single export phrase: export A=1 B=2 C=3 Testing: $ (export A=1 B=2 C=3 && ksh -c ‘echo A=$A B=$B C=$C D=$D’) A=1 B=2 C=3 D= Awkward alternatives There is … Read more
How to write Unix shell scripts with options?
$ cat stack.sh #!/bin/sh if [[ $1 = “-o” ]]; then echo “Option -o turned on” else echo “You did not use option -o” fi $ bash stack.sh -o Option -o turned on $ bash stack.sh You did not use option -o FYI: $1 = First positional parameter $2 = Second positional parameter .. = … Read more
How do I use a guid in a mongodb shell query
You can use easily: .find({ “_id” : CSUUID(“E3E45566-AFE4-A564-7876-AEFF6745FF”)})
Why I’m getting unexpected EOF for my cron job?
You may need to escape the % with a \. % is a special character to the crontab, which gets translated to a newline, so your code was probably becoming -p’]T zw51′ Try: -p’]T\%zw51′
How to run commands via NodeJS child process?
Sending a newline \n will exectue the command. .end() will exit the shell. I modified the example to work with bash as I’m on osx. var terminal = require(‘child_process’).spawn(‘bash’); terminal.stdout.on(‘data’, function (data) { console.log(‘stdout: ‘ + data); }); terminal.on(‘exit’, function (code) { console.log(‘child process exited with code ‘ + code); }); setTimeout(function() { console.log(‘Sending stdin … Read more
-z option inside if condition in shell script
From “help test”: -z STRING True if string is empty.
How to reverse lines of a text file?
In GNU coreutils, there’s tac(1)
How do I find the latest version of an artifact from a maven repository
You can use the Maven Dependency Plugin goal get together with LATEST as version for your artifact: mvn org.apache.maven.plugins:maven-dependency-plugin:2.8:get -DremoteRepositories=<URL_to_your_maven_repo> -Dartifact=<group_id>:<artifact_id>:LATEST -Dpackaging=jar -Ddest=<target_dir>/<artifact_name>.jar
How portable is mktemp(1)?
POSIX does not seem to specify mktemp(1). It looks like most modern systems have it, but the available functionality and the semantics of the options vary between implementations (so particular invocations may not be portable): mktemp(1) from OpenBSD — mktemp(1) originated in OpenBSD 2.1 mktemp(1) from FreeBSD mktemp(1) from Mac OS X — almost always … Read more