Escaping hyphens (–) with printf in bash

bash

I have the following line:

printf "---- %.55s\n" "$1 --------------"

When I run this under bash I get the following error:

printf: –: invalid option printf: usage: printf [-v var] format
[arguments]

This is because (I think) printf interprets the string "—-" as the beginning of an argument. I have tried to escape this using "\" like so:

printf "\---- %.55s\n" "$1 --------------"

The following is the result:

\---- content of $1 -------

As you can see the "\" became part of the output which is not what I want.

So the question is, how can i persuade printf that I am not trying to pass a long argument?

Best Answer

To avoid an argument starting in - being interpreted as an option, you have a few different alternatives:

1) Move the minus signs form the format string to the argument string, possibly reflecting the new length of the printed string in the %.s format specifier. As in:

$ printf "%.60s\n" "---- $1 --------------"

2) bash's builtin commands accept -- as an option that instructs them to stop processing options and consider everything that follows as file-names and arguments. As in:

$ printf -- "---- %.55s\n" "$1 --------------"

3) You can substitute the minus signs with their octal codes. Actually, replacing just the first one works, as in:

$ printf "\055--- %.55s\n" "$1 --------------"

Related Solutions

Run python oneliner in bash script

There is no need for escaping or moving the argument to its own variable.

But, keeping it mostly the same, the following works for me:

#!/usr/bin/env bash
WS="/Users/danielbeck/Desktop"
PY_GET_MVN_VERS="from xml.dom.minidom import parse;dom = parse('${WS}/pom.xml');print [n.firstChild.data for n in dom.childNodes[0].childNodes if n.firstChild and n.tagName == 'version']"
function test_mvn {
        MVN_VER=$( python -c "${PY_GET_MVN_VERS}" )
        echo ${MVN_VER}
}
test_mvn

/Users/danielbeck/Desktop/pom.xml is the example minimal POM from the Maven docs:

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.mycompany.app</groupId>
  <artifactId>my-app</artifactId>
  <version>1</version>
</project>

Output:

[u'1']

Please throw away your code and just use mine (after adjusting WS) instead of adjusting yours until it works. You have quite a few syntax errors in there.

Linux – How to run a sequence of bash scripts one at a time in Linux

Simplest way to run one command after another is just to use ; Like:

command1 --options;command2 --options;command3 --options

If you wish to skip running commands if the previous one fails, you can do it with &&:

 command1 --options && command2 --options && command3 --options

Unlike pipe (|) or ampersand (&), the semicolon waits for the command to finish before the next command is run.

Best Answer

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Run python oneliner in bash script

Linux – How to run a sequence of bash scripts one at a time in Linux

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