PHPSeclib additional line breaks using write

Question

I'm getting close to the point of simply moving this back to PERL for a specific use case of editing files via SSH. It seems no matter what I do, additional line breaks are being placed in the file. Sample variable has the following:

req_extensions = v3_req
prompt = no
[req_distinguished_name]
C = US

Using the following command, I get the output below

$ssh->write("echo '$file' > /directory/test.txt\n");

Resulting in:

req_extensions = v3_req

prompt = no

[req_distinguished_name]

C = US

Edit adding relevant debug log:

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0022, network: 0s)
00000000  00:00:00:02:00:00:00:01:65                       ........e

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0005, network: 0.0001s)
00000000  00:00:00:02:00:00:00:01:63                       ........c

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0005, network: 0s)
00000000  00:00:00:02:00:00:00:01:68                       ........h

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0003, network: 0s)
00000000  00:00:00:02:00:00:00:01:6f                       ........o

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0005, network: 0.0003s)
00000000  00:00:00:02:00:00:00:01:20                       ........ 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0004, network: 0s)
00000000  00:00:00:02:00:00:00:01:27                       ........'

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0.0001s)
00000000  00:00:00:02:00:00:00:01:72                       ........r

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:65                       ........e

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0003, network: 0.0002s)
00000000  00:00:00:02:00:00:00:01:71                       ........q

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:5f                       ........_

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:65                       ........e

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0007, network: 0.0006s)
00000000  00:00:00:02:00:00:00:01:78                       ........x

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0003, network: 0s)
00000000  00:00:00:02:00:00:00:01:74                       ........t

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0.0001s)
00000000  00:00:00:02:00:00:00:01:65                       ........e

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0003, network: 0.0002s)
00000000  00:00:00:02:00:00:00:01:6e                       ........n

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0s)
00000000  00:00:00:02:00:00:00:01:73                       ........s

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:69                       ........i

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0005, network: 0.0002s)
00000000  00:00:00:02:00:00:00:01:6f                       ........o

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0005, network: 0s)
00000000  00:00:00:02:00:00:00:01:6e                       ........n

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:73                       ........s

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:20                       ........ 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0004, network: 0s)
00000000  00:00:00:02:00:00:00:01:3d                       ........=

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:20                       ........ 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0s)
00000000  00:00:00:02:00:00:00:01:76                       ........v

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:33                       ........3

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0s)
00000000  00:00:00:02:00:00:00:01:5f                       ........_

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0s)
00000000  00:00:00:02:00:00:00:01:72                       ........r

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:65                       ........e

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0.0001s)
00000000  00:00:00:02:00:00:00:01:71                       ........q

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:02:0d:0a                    ..........

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:02:3e:20                    ........> 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0005, network: 0.0004s)
00000000  00:00:00:02:00:00:00:02:0d:0a                    ..........

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:02:3e:20                    ........> 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:70                       ........p

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:72                       ........r

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:6f                       ........o

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:6d                       ........m

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0.0001s)
00000000  00:00:00:02:00:00:00:01:70                       ........p

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0s)
00000000  00:00:00:02:00:00:00:01:74                       ........t

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:20                       ........ 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0s)
00000000  00:00:00:02:00:00:00:01:3d                       ........=

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:20                       ........ 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0.0002s)
00000000  00:00:00:02:00:00:00:01:6e                       ........n

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:01:6f                       ........o

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0002, network: 0.0002s)
00000000  00:00:00:02:00:00:00:02:0d:0a                    ..........

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:02:3e:20                    ........> 

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:02:0d:0a                    ..........

<- NET_SSH2_MSG_CHANNEL_DATA (since last: 0.0001, network: 0s)
00000000  00:00:00:02:00:00:00:02:3e:20                    ........>

TIA

I don't want the additional line breaks that aren't actually in my string. — networkguy858, Jul 19 '18 at 18:41
Would need to see the hex for that string variable I think? CR and LF perhaps? — ficuscr, Jul 19 '18 at 18:43
You added `\n` in the end of that command. Remove that and it will remove the newline. Your command can be `$ssh->write("echo '$file' > /directory/test.txt");` — Shaharia Azam, Jul 19 '18 at 18:45
^ Wondered about that too. Wouldn't that just get you `test.txtn`? — ficuscr, Jul 19 '18 at 18:49
@ShahariaAzam - the \n was just to force carriage return. Removing it doesn't make any difference - I still get the "test.txt" file with unintended line breaks compared with the string. — networkguy858, Jul 19 '18 at 19:08

score 1 · Answer 1 · answered Jul 19 '18 at 19:12

1

Just pass -n and it should fix that.

$ssh->write("echo -n '$file' > /directory/test.txt\n");

-n tell not to append a new line.

answered Jul 19 '18 at 19:12

Shaharia Azam

1,948
19
25

Same result as before – networkguy858 Jul 19 '18 at 19:20
1

According to http://linuxcommand.org/lc3_man_pages/echoh.html `echo` man page. `-n` should solve this. Though it worked for me. See my gist on https://gist.github.com/shahariaazam/d1d3b2c2af76ca2124eeecca814bc947 – Shaharia Azam Jul 19 '18 at 19:38
1

Also I found the similar question's solutions here at https://stackoverflow.com/a/38021361/1431786 – Shaharia Azam Jul 19 '18 at 19:40
Right - echo isn't the problem here, it's whatever phpseclib is doing with the "write" method that I believe to be the issue. I can take the same text and echo no problem via a native shell. – networkguy858 Jul 19 '18 at 19:40
2

You can use `exec()` method for that if the `write` method have any problem. Also what's the OS of your remote server? – Shaharia Azam Jul 19 '18 at 19:43
The server I'm running the commands on is FreeBSD, no matter what I do with `exec()`, it doesn't work. – networkguy858 Jul 19 '18 at 19:55
Would still like to know what `$file` is. You are certain the extra line breaks are not there? – ficuscr Jul 19 '18 at 20:17
Of course - no additional line breaks in $file. It's as I wrote at the start. – networkguy858 Jul 19 '18 at 20:22
I'll... I suppose... I guess I'll take your word for it :) Do wonder though about the 4 lines shown between the `q` and `p` in the debug output you shared. – ficuscr Jul 19 '18 at 20:29
Sorry to prolong this - just to add,`exec()` does actually put it in correctly, but my problem is I have an @ symbol in part of the text which is why `exec()` doesn't work for me. I can always use sed to fix this I suppose, was just hoping for a better way. – networkguy858 Jul 19 '18 at 20:51
2

Too beat the horse further.. Why not use `put`? – ficuscr Jul 19 '18 at 21:08
@ficuscr - I wanted to chain additional commands, I'm going that route. – networkguy858 Jul 19 '18 at 23:29

score 0 · Answer 2 · answered Jul 19 '18 at 23:34

I'm not sure why write() was sending additional line breaks. I'm sure if I went line by line and appended to the file that would have worked. In the end, I simply used SFTP::put() which allowed me to place the @ that which wouldn't work with SSH::exec(). Thanks for all the input - it's a little different method than I would have liked, but it works.

PHPSeclib additional line breaks using write

2 Answers2