bash：在 cron 作业中使用 scp 失败，但从命令行运行时运行成功

Question

我正在尝试在由 cron 运行的 bash 脚本中使用 scp（我在 Ubuntu 10.0.4 LTS 上运行它）。

该脚本工作正常（即，当我从命令行运行它时，向/从远程服务器传输和复制 file1 和 file2。但是，当我将脚本作为 cron 作业运行时，它失败了。

这就是脚本的样子：

#!/bin/bash

cd /home/oompah/scripts/tests/
scp -P 12345 file1 oompah@someserver.com:~/uploads

if scp -P 12345 oompah@someserver.com:/path/to/file2.dat local.dat >&/dev/null ; then 
    echo "INFO: transfer OK" ; 
else 
    echo "ERROR: transfer failed" ; 
fi

当我将它作为 cron 作业运行时，我得到的错误消息（重定向到日志文件）是：

ERROR: transfer failed

我发送到我的邮件收件箱的错误消息是：

Permission denied (publickey).
lost connection

为什么会发生，我该如何解决？

[编辑]

我用 -i 命令修改了第一个 scp 命令（如 M Jenkins 建议的那样），我还添加了 -v 用于调试消息。这是完整的调试消息日志。希望它可以阐明正在发生的事情：

Executing: program /usr/bin/ssh host 12.34.56.78, user oompah, command scp -v -t ~/uploads
OpenSSH_5.3p1 Debian-3ubuntu6, OpenSSL 0.9.8k 25 Mar 2009
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to 12.34.56.78 [12.34.56.78] port 12345.
debug1: Connection established.
debug1: identity file /home/oompah/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3p1 Debian-3ubuntu3
debug1: match: OpenSSH_5.3p1 Debian-3ubuntu3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu6
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host '[12.34.56.78]:12345' is known and matches the RSA host key.
debug1: Found key in /home/oompah/.ssh/known_hosts:3
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/oompah/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: PEM_read_PrivateKey failed
debug1: read PEM private key done: type <unknown>
debug1: read_passphrase: can't open /dev/tty: No such device or address
debug1: No more authentication methods to try.
Permission denied (publickey).
lost connection
Permission denied (publickey).

Answer 1

我猜：

您有一个受密码保护的 SSH 密钥对，它会在您登录时由 GNOME Keyring 自动加载。但是，cron无法访问密钥环，ssh也不能要求输入密码（由于缺少 tty）。

引用ssh您添加的日志：

debug1：提供公钥：/home/oompah/.ssh/id_rsa
debug1：服务器接受密钥：pkalg ssh-rsa blen 277
debug1：PEM_ read_PrivateKey 失败
debug1：读取 PEM 私钥完成：键入
debug1：read_passphrase：无法打开 / dev/tty : 没有这样的设备或地址