用netcat打印后记

netcat程序可用于与postscript打印机进行双向通信。

我一直在使用一些简单的程序将打印作业直接发送到网络postscript打印机,到目前为止还没有从打印机收到任何返回信息。我喜欢直接与打印机通信,而不是将作业发送到后台处理程序。

关于用netcat打印的信息很少,所以我做这份报告。

我的打印机是Xerox 6500n,通过以太网电缆连接到路由器。我可以通过多种方式将postscript程序或pdf文件直接发送到打印机。有时我想从打印机中获取答案,因此有一个测试程序可以使用打印机使用“pathforall”转换输入并发回答案。netcat做得很好:

nc -n 192.168.1.111 9100 < pathforall.ps

然后我得到了想要的回应。这已经过检查,与ghostscript输出类似,只是出于某种原因略有偏差:

$ nc -v -w 5 -n 192.168.1.111 9100 < pathforall.ps
192.168.1.111 9100 (hp-pdl-datastr) open
28.6998 12.2999 moveto
28.6998 9.29996 28.3998 8.09995 25.2998 6.59998 curveto
24.3998 6.09998 21.2999 4.79999 19.0999 4.79999 curveto
15.3999 4.79999 12.4999 7.89996 12.4999 12.5999 curveto
12.4999 12.7999 lineto
12.4999 16.1999 13.5999 21.7999 28.6998 26.7999 curveto
closepath

$ gs pathforall.ps
GPL Ghostscript 9.50 (2019-10-15)
Copyright (C) 2019 Artifex Software, Inc.  All rights reserved.
This software is supplied under the GNU AGPLv3 and comes with NO WARRANTY:
see the file COPYING for details.
Loading Times-Roman font from /usr/share/ghostscript/fonts/Times-Roman.pfa... 4824712 3114962 3833824 2546359 1 done.
28.6184 12.2615 moveto
28.6184 9.27632 28.3224 8.07977 25.2262 6.57484 curveto
24.3257 6.08141 21.2418 4.78618 19.0461 4.78618 curveto
15.3577 4.78618 12.4589 7.8824 12.4589 12.5576 curveto
12.4589 12.7673 lineto
12.4589 16.1472 13.5567 21.7352 28.6184 26.7188 curveto
28.6184 12.2615 lineto
closepath

netcat允许我与打印机进行类似于ghostscript的通信,只是我还没有启动执行模式。此外,请确保在postscript中包含“flush”命令,以将整个答案发送回。 这可用于从打印机获取信息的多种目的。

编辑:这里有一个简单的测试,看看打印机STDOUT是否正在返回计算机:

%!
(Hello World\n) print flush

EDIT3:正如luser droog所建议的那样,后记执行模式使用telnet在Xerox 6500n上运行。请参阅下面的评论。

这里有一个bash/dev/tcp替代方案,用于在没有netcat的情况下进行打印。 如果使用--enable-net重定向构建,则使用bash将其发送到网络PostScript打印机。这适用于我的Void bash和Xerox Phaser 6500n,并在PJL和PostScript之间切换。其他打印机的测试结果会有所帮助。

#!/bin/bash
#
#   ++++   driverless postscript printing   ++++
#   bash needs --enable-net-redirections build option
#
# for postscript programs with postscript printer only
#
# bash escape is \033 or \e or \E or \x1B

exec 5<>/dev/tcp/192.168.1.111/9100 || exit 1     # change ip as needed

{
 echo -e "\E%-12345X@PJL"           # PJL entrance
 echo @PJL ECHO "$(date)"
 echo @PJL ECHO "setting up printer ..."
 echo @PJL COMMENT Change Printer Settings
 echo @PJL SET COPIES = 1           # modify environment settings
 echo @PJL SET MANUALFEED = off
 echo @PJL ECHO "Starting PostScript Program ..."
 echo @PJL ENTER LANGUAGE = POSTSCRIPT
 echo  "%!"                         # optional
cat "$1" || echo -E "(Hello World\n) print flush"   # if input.ps missing
 echo -e "\004"                     # ctrl-D for end of file
 echo -e "\e%-12345X@PJL"           # back to PJL
 echo @PJL ECHO "Finished PostScript Program."
 echo @PJL RESET                    # unset modified environment settings
 echo @PJL ECHO BYE.
 echo -e "\033%-12345X"             # PJL universal exit
} >&5                               # send to printer

while read -t 122 -r LINE            # timeout after 122 seconds of silence
do
  echo "$LINE"
if [[ "$LINE" =~ @PJL\ ECHO\ BYE. ]]; then break; fi
done <&5

echo "Finished reading printer"

exec 5>&-                           # close
exec 5<&-                           # close both
exit 0

这是我终端中的结果。一定要发送一个类似“print.sh input.ps”的文件,否则会发生这种情况:

$ ./print.sh
cat: '': No such file or directory
@PJL ECHO Mon 20 Apr 2020 07:10:03 AM PDT

@PJL ECHO setting up printer ...

@PJL ECHO Starting PostScript Program ...

Hello World
@PJL ECHO Finished PostScript Program.

@PJL ECHO BYE.
Finished reading printer

更新:我在这里添加了这个: github