How to replace ${} placeholders in a text file?

bash command-line text-processing templating
Dana the Sane picture Dana the Sane · Jan 6, 2009 · Viewed 158.7k times · Source

I want to pipe the output of a "template" file into MySQL, the file having variables like ${dbName} interspersed. What is the command line utility to replace these instances and dump the output to standard output?

Answer

user picture user · Jan 6, 2009

Sed!

Given template.txt:

The number is ${i}
The word is ${word}

we just have to say:

sed -e "s/\${i}/1/" -e "s/\${word}/dog/" template.txt

Thanks to Jonathan Leffler for the tip to pass multiple -e arguments to the same sed invocation.

Related questions

How do I set a variable to the output of a command in Bash?

I have a pretty simple script that is something like the following: #!/bin/bash VAR1="$1" MOREF='sudo run command against $VAR1 | grep name | cut -c7-' echo $MOREF When I run this script from the command line and pass it …

Read More
How do I parse command line arguments in Bash?

Say, I have a script that gets called with this line: ./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile or this one: ./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile What's the accepted way of parsing this such …

Read More
How to count lines in a document?

I have lines like these, and I want to know how many lines I actually have... 09:16:39 AM all 2.00 0.00 4.00 0.00 0.00 0.00 0.00 0.00 94.00 09:16:40 AM all 5.00 0.00 0.00 4.00 0.00 0.00 0.00 0.00 91.00 09:16:41 AM all 0.00 0.00 4.00 0.00 0.00 0.00 0.00 0.00 96.00 09:16:42 AM all 3.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00 96.00 09:16:43 AM all 0.00 0.00 1.00 0.00 1.00 0.00 0.00 0.00 98.00 09:16:44 AM all 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00 09:16:45 AM all 2.00 0.00 6.00 0.00 0.00 0.00 0.00 0.00 92.00 Is there a way to count them all using linux …

Read More