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If you have a HyperSQL (HSQL) database stored in a file, it is often useful to be able to query that database from the command line. This can be done using the following command: By default, user SA with no password will exist for each database file. If the database does not exist, it will be created …

There are many ways in the linux terminal to print the nth word of a given file or output. One way to do this without worrying about tabs, extra spaces or word length is to use awk. With awk, this can be done on one line by using the {print $<n>} syntax. For example, the ps command may print this: To …

With Docker, you can specify the command to run inside the container on the command line. But what if you want to run multiple commands? You can’t escape the && syntax, or wrap the command in quotes, as Docker won’t recognise it. The trick here is to use For example, to run date and whoami in a vanilla ubuntu container, we would run …

Awk is a useful language for many command line tasks. Often awk is used on the command line on its own or with strings piped to it, but it is possible to turn that awk code into an executable script. Consider the following script. This file contains awk code with a shebang of awk -f. The -f is …

In awk, fields are accessed by number; $1 for the first field, $2 for the second, etc. But sometimes the field number you want to access is not known until run time. In these cases, you can access the field using the $(<index>) syntax. The constant NF contains the number of fields available. For example, you can print all fields with their field …