linux 转换工具 convert的使用

最近运行如下类似的命令：

convert f.jpg f.eps

报错：

convert: not authorized `f.eps' @ error/constitute.c/WriteImage/1028.

于是我好好看了下convert这个命令工具， 发现convert实现了bzlib cairo djvu fftw fontconfig freetype jbig jng jpeg lcms lqr ltdl lzma openexr pangocairo png rsvg tiff wmf x xml zlib等格式的相互转换。看着就比较实用。convert是imagemagick的一个子工具。
安装convert的工具包imagemagick：

sudo apt install imagemagick

报错解决方案

在askubuntu, 找到了解决方案， 就是修改 /etc/ImageMagick-6/policy.xml文件， 修改如下：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policymap [
<!ELEMENT policymap (policy)+>
<!ELEMENT policy (#PCDATA)>
<!ATTLIST policy domain (delegate|coder|filter|path|resource) #IMPLIED>
<!ATTLIST policy name CDATA #IMPLIED>
<!ATTLIST policy rights CDATA #IMPLIED>
<!ATTLIST policy pattern CDATA #IMPLIED>
<!ATTLIST policy value CDATA #IMPLIED>
]>
<!--
  Configure ImageMagick policies.

  Domains include system, delegate, coder, filter, path, or resource.

  Rights include none, read, write, and execute.  Use | to combine them,
  for example: "read | write" to permit read from, or write to, a path.

  Use a glob expression as a pattern.

  Suppose we do not want users to process MPEG video images:

    <policy domain="delegate" rights="none" pattern="mpeg:decode" />

  Here we do not want users reading images from HTTP:

    <policy domain="coder" rights="none" pattern="HTTP" />

  Lets prevent users from executing any image filters:

    <policy domain="filter" rights="none" pattern="*" />

  The /repository file system is restricted to read only.  We use a glob
  expression to match all paths that start with /repository:
  
    <policy domain="path" rights="read" pattern="/repository/*" />

  Any large image is cached to disk rather than memory:

    <policy domain="resource" name="area" value="1GB"/>

  Define arguments for the memory, map, area, and disk resources with
  SI prefixes (.e.g 100MB).  In addition, resource policies are maximums for
  each instance of ImageMagick (e.g. policy memory limit 1GB, -limit 2GB
  exceeds policy maximum so memory limit is 1GB).
-->
<policymap>
  <!-- <policy domain="resource" name="temporary-path" value="/tmp"/> -->
  <!-- <policy domain="resource" name="memory" value="2GiB"/> -->
  <!-- <policy domain="resource" name="map" value="4GiB"/> -->
  <!-- <policy domain="resource" name="area" value="1GB"/> -->
  <!-- <policy domain="resource" name="disk" value="16EB"/> -->
  <!-- <policy domain="resource" name="file" value="768"/> -->
  <!-- <policy domain="resource" name="thread" value="4"/> -->
  <!-- <policy domain="resource" name="throttle" value="0"/> -->
  <!-- <policy domain="resource" name="time" value="3600"/> -->
  <!-- <policy domain="system" name="precision" value="6"/> -->
  <policy domain="cache" name="shared-secret" value="passphrase"/>
  <policy domain="coder" rights="none" pattern="EPHEMERAL" />
  <policy domain="coder" rights="none" pattern="URL" />
  <policy domain="coder" rights="none" pattern="HTTPS" />
  <policy domain="coder" rights="none" pattern="MVG" />
  <policy domain="coder" rights="none" pattern="MSL" />
  <policy domain="coder" rights="none" pattern="TEXT" />
  <policy domain="coder" rights="none" pattern="SHOW" />
  <policy domain="coder" rights="none" pattern="WIN" />
  <policy domain="coder" rights="none" pattern="PLT" />
  <policy domain="path" rights="none" pattern="@*" />
  <!-- disable ghostscript format types -->
  <policy domain="coder" rights="none" pattern="PS" />
  
  <!-- 把eps这一样注释掉-->
  <!-- <policy domain="coder" rights="none" pattern="EPS" />--> 
  <!-- ------------- -->

  <policy domain="coder" rights="none" pattern="PDF" />
  <policy domain="coder" rights="none" pattern="XPS" />
</policymap>

重新运行convert 转换命令就没有问题了。

我的环境是ubuntu 16.04的， 发现没有 fig2dev， 我在网上找的deb包进行安装。
查找可执行文件：

find /home -type f -perm -111