Visit Our UNIX and Linux User Community


Double quotes or single quotes when using ssh?


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Double quotes or single quotes when using ssh?
# 1  
Old 05-28-2008
Double quotes or single quotes when using ssh?

I'm not very familiar with the ssh command. When I tried to set a variable and then echo its value on a remote machine via ssh, I found a problem. For example,

$ ITSME=itsme
$ ssh xxx.xxxx.xxx.xxx "ITSME=itsyou; echo $ITSME"
itsme
$ ssh xxx.xxxx.xxx.xxx 'ITSME=itsyou; echo $ITSME'
itsyou
$

So what was going on here? Which satement was executed on remote machine and which one was on local system? I'm a little confused ....
# 2  
Old 05-28-2008
Check the links below.
# 3  
Old 05-28-2008
Double quotes don't prevent variables from being expanded locally. So the remote host sees "ITSME=itsyou; echo itsme" in the first case.
# 4  
Old 05-29-2008
Quote:
Originally Posted by era
Double quotes don't prevent variables from being expanded locally. So the remote host sees "ITSME=itsyou; echo itsme" in the first case.
So the two statements: ITSME=itsyou & echo $ITSME are both executed on remote host. But in the case of double quotes, variable will be evaluated first so the argument passed to ssh is actually ITSME=itsyou; echo itsme. While in the case of single quotes, no special characters survive. The argument passed to ssh is ITSME=itsyou; echo $ITSME. Understood, this is really an issue of command-line processing.

Previous Thread | Next Thread
Test Your Knowledge in Computers #554
Difficulty: Medium
Using printf() in C, %d formats a decimal variable or literal.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Replace Double quotes within double quotes in a column with space while loading a CSV file

Hi All, I'm unable to load the data using sql loader where there are double quotes within the double quotes As these are optionally enclosed by double quotes. Sample Data : "221100",138.00,"D","0019/1477","44012075","49938","49938/15043000","Television - 22" Refurbished - Airwave","Supply... (6 Replies)
Discussion started by: mlavanya
6 Replies

2. Shell Programming and Scripting

Replace double quotes with a single quote within a double quoted string

Hi Froum. I have tried in vain to find a solution for this problem - I'm trying to replace any double quotes within a quoted string with a single quote, leaving everything else as is. I have the following data: Before: ... (32 Replies)
Discussion started by: pchang
32 Replies

3. Shell Programming and Scripting

Issue with Single Quotes and Double Quotes for prompt PS1

Hi, Trying to change the prompt. I have the following code. export PS1=' <${USER}@`hostname -s`>$ ' The hostname is not displayed <abc@`hostname -s`>$ uname -a AIX xyz 1 6 00F736154C00 <adcwl4h@`hostname -s`>$ If I use double quotes, then the hostname is printed properly but... (3 Replies)
Discussion started by: bobbygsk
3 Replies

4. UNIX for Dummies Questions & Answers

awk for inserting a variable containing single and double quotes

Hi i have to insert the below line into a specific line number of another file export MBR_CNT_PRCP_TYPE_CODES_DEL="'01','02','04','05','49','55','UNK'" I have passed the above line to a variable say ins_line. I have used below command to perform the insert awk 'NR==3{print "'"${ins_line}"'"}1'... (1 Reply)
Discussion started by: sathishteradata
1 Replies

5. Shell Programming and Scripting

Having a terrible problem with quotes/single quotes!

Hello. I'm trying to write a bash script that uses GNU screen and have hit a brick wall that has cost me many hours... (I'm sure it has something to do with quoting/globbing, which is why I post it here) I can make a script that does the following just fine: test.sh: #!/bin/bash # make... (2 Replies)
Discussion started by: jondecker76
2 Replies

6. UNIX for Dummies Questions & Answers

Unable to send single and double quotes to command

Hi Unix experts, Believe me, this forum has been really great help and I searched for many things that were already answered before open new post that were just new versions of old one, but with this one, I just can't simply move any forward. This must be quite easy, but I cant find where I... (1 Reply)
Discussion started by: manolain
1 Replies

7. UNIX for Dummies Questions & Answers

grep single quotes or double quotes

Unix superusers, I am new to unix but would like to learn more about grep. I am very familiar with regular expressions as i have used them for searching text files in windows based text editors. Since I am not very familiar with Unix, I dont understand when one should use GREP with the... (2 Replies)
Discussion started by: george_vandelet
2 Replies

8. Shell Programming and Scripting

Single quotes and double quotes

Hi guys, I have a sed line in double quotes which works fine, but I want it to be in single quotes here is the sed line sed "/abc_def/s/\'.*\'/\'\${abc_def}\'/" can some one give the equivalent to the above script in single quotes Thanks a ton (5 Replies)
Discussion started by: sol_nov
5 Replies

9. Shell Programming and Scripting

How to alias an awk command with single and double quotes?

Hi, I am trying to write the following command as an alias in my .bashrc file. bjobs -u all | awk '{if (NR > 1) {username++;}}END{{print"\nJOBS BY USER:\n"} for (i in username) {print username,i;}{print"\n Total Jobs=",NR-1,"\n" }}' The command simply puts how many jobs each user is... (2 Replies)
Discussion started by: jacekmaciek
2 Replies

10. UNIX for Dummies Questions & Answers

grep exclude/find single and double quotes

Hello, I'm trying to use grep or egrep to exclude a whole range of characters but how do I exclude both a single and a double quote. It might be easier to say how do I use grep to find both single and double quotes. grep ' ' " ' file grep detects the first single quote within my... (4 Replies)
Discussion started by: Lindy_so
4 Replies

Featured Tech Videos