---
name: "escape"
section: "1"
platform: "linux"
package: "mailavenger"
version: "0.8.5-1"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/escape"
---

# escape(1)

escape shell special characters in a string

## NAME

escape - escape shell special characters in a string

## SYNOPSIS

escape *string*

## DESCRIPTION

escape prepends a `"\"` character to all shell special characters in *string*, making it safe to compose a shell command with the result.

## EXAMPLES

The following is a contrived example showing how one can unintentionally end up executing the contents of a string:

```
    $ var='; echo gotcha!'
    $ eval echo hi $var
    hi
    gotcha!
    $
```

Using escape, one can avoid executing the contents of `$var`:

```
    $ eval echo hi `escape "$var"`
    hi ; echo gotcha!
    $
```

A less contrived example is passing arguments to Mail Avenger bodytest commands containing possibly unsafe environment variables.  For example, you might write a hypothetical *reject\_bcc* script to reject mail not explicitly addressed to the recipient:

```
    #!/bin/sh
    formail -x to -x cc -x resent-to -x resent-cc \
        | fgrep "$1" > /dev/null \
            && exit 0
    echo "<$1>.. address does not accept blind carbon copies"
    exit 100
```

To invoke this script, passing it the recipient address as an argument, you would need to put the following in your Mail Avenger *rcpt* script:

```
    bodytest reject_bcc `escape "$RECIPIENT"`
```

## SEE ALSO

[**avenger**(1)](/avenger/1.md),

The Mail Avenger home page: \<http://www.mailavenger.org/\>.

## BUGS

escape is designed for the Bourne shell, which is what Mail Avenger scripts use.  escape might or might not work with other shells.

## AUTHOR

David Mazieres