WARNING! Getting pretty basic here guys...
I have a rather elaborate shell script that I wish to create, but am haveing difficulty with the most basic of commands so am struggling to get going.
I want to create a .sh file that I can simply run using BASH -
If I place just CD in the file and run in BASH nothing happens, whereas running CD from the terminal obv. gets me home.
Could someone shed some light on this please... I am running OSX
thanks
When you run a script you spawn a new sub-shell, your cd works in that and then you exit back to your orginal shell and your old present work directory - just as thought the cd never happened. If you want to short cut cds use a alias or a function. Something like:
go_dev() {
cd /my/long/path/to/dev/env/
}
or
alias go_dev='cd /my/long/path/to/dev/env/'
Related
I am trying to learn the basics of shell. I used vim editro for creating my own list of commands to be executed. Here is the way I created the code
vi mycommands
then inside this file I wrote
cd Documents
I am using macOS Catalina which has zsh by default but switched to bash
So when I write the following command in the terminal:
$ sh +x mycommands
It shows
+cd Documents
The Documents has some files and directories but it is not changing directory.Where am I going wrong?
Any help will be greatly appreciated.
Scripts run like sh myscript execute in a separate sub-shell, not the current shell. Changing directory inside a script will not cause your shell to change directory. If you want to change directory in your shell, you need to run the commands in your shell.
To do that, run:
. ./myscript (sh, bash) or source ./myscript (bash).
See this question.
I am having some issue in writing a simple executable .sh file via bash.
The order of operation as soon as I open a terminal (ctrl+alt+T) are:
pc:~$ roscd
pc:~/catkin_docking_ws/devel$ cd ..
pc:~/catkin_docking_ws$ cd devel/lib/tuginterface/
pc:~/catkin_docking_ws/devel/lib/tuginterface$ ./tuginterface
I have been investigating this small issue and came across this source which advises to change and rename the project as an alias and that is exactly what I tried to do:
alias proj="roscd"
alias proj2="cd .."
alias proj3="cd devel/lib/tuginterface/"
alias exec="./tuginterface"
My current executable file after many trials is:
#!/bin/bash
alias proj="roscd"
alias proj2="cd .."
alias proj3="cd devel/lib/tuginterface/"
alias exec="./tuginterface"
But it still does not work.
The same post advises to create a script and after that an alias in the startup file.
Please advise on how to solve this problem and sorry if it is a simple question but I don't seem to catch the mistake I am making.
The script doesn't need to define aliases. Aliases are commands that you can type yourself. The script can just execute the commands directly.
#!/bin/bash
cd ~/catkin_docking_ws/devel/lib/tuginterface
./tuginterface
I've combined the three cd commands into one that jumps straight to the correct directory.
"But I thought cd doesn't work in shell scripts?"
It depends what you're looking for. When a script changes directory it affects later commands in the script, so in that respect it does work. The change of directory is only inside the script, though. The person calling the script won't see the directory change. Their current directory is unaffected.
I have a Perl program on server_B which uses Perl DBI and 5.010 and runs fine from the server_B terminal. I run it from a shell script which first prepares some arguments and then passes them to the Perl program, all works fine.
I need to run a shell script on server_A that will execute that script on server_B. This is because the Perl program creates several files that I want to SFTP back over to server_A. This is the script I'm running on server_A:
ssh server_B <<- EOF
perl/update.sh
EOF
There is some strange behavior which I'm trying to understand:
The script (update.sh) on server_B runs mysql, which is not installed on server_A (which is why I have to do this whole thing.) If I try to run it on server_B as-is, I can call mysql just like that. But when I run the above script (on server_A) to ssh into server_B and run that script, it doesn't recognize mysql unless I change the file (on server_B) to call the full path /opt/mysql/client/bin/mysql (even though that file is already on server_B with mysql installed) Does this mean server_B is picking up on the PATH variable from server_A instead of using my PATH variable from server_B? Is it trying to run my programs from server_A on the files on server_B? How and why??
If I make the change above it executes the script, but when it hits Perl it says
Perl v5.10.0- required - this is only v5.8.8
Again, 5.10 works fine on server_B but the version of Perl on server_A is 5.8.8.
So I got rid of use 5.010; because it actually wasn't necessary, but then I have a similar problem with my modules (DBI and DBD::mysql). I get:
Can't locate DBI.pm in #INC (#INC contains.. [my Perl PATH from server_A])
at perlfile.pl line 4
I was expecting the ssh heredoc call to update.sh (from server_A) to run exactly as update.sh does if I call it on server_B, but instead it seems like it's trying to use my programs from server_A on server_B, which I find weird. Can anyone help me understand why it's happening? I feel like I'm misunderstanding something fundamental about how ssh works.
server_A is AIX with ksh
server_B is AIX with bash
Edit - since some of you voted to the effect that I haven't done my research, here's what else I've tried. I didn't mention because I don't understand them fully, these are just guesses based on other SO posts & hunches. It'd be disingenuous if I gave the impression I knew what I was talking about.
If this is a duplicate, which question should I be looking at? If this is a "just read the manual situation", which one? What should I look for?
Read man ssh looking for clues related to environment variables, didn't find anything I understood
Tried running with -t
Tried running with -t -t
Did log in remotely with ssh and manually running it - this DOES work
Sourced my .bash_profile in the update script
Tried to re-assign PATH as the remote server's PATH when ssh
Tried using a different delimiter for the heredoc
Tried < instead of <<
Tried without the "-"
Edit 2 with Saigo's help below I determined that when in interactive ssh, if I echo $PATH I do get the target server's $PATH, but in a shell script I don't. That led me to this:
https://serverfault.com/questions/643333/different-bash-path-variables-when-using-ssh-script-vs-interactive-ssh
where I found out that scripted ssh doesn't call .bashrc, but interactive ssh does. So it looks like I was on the right track trying to source .bash_profile inside the scripted SSH heredoc, just need .bashrc not .bash_profile - however I don't have a .bashrc on the target server. I do have .profile but when I source that, I get an error stating it's for interactive bash sessions only. So now I'm just trying to find whatever file would contain my $PATH variable because it's apparently not .bashrc as there isn't one in there.
Edit 3 - tried hard-coding the PATH variable into a file and sourcing that and even then when I echo $PATH I get the origin server's PATH variable. It is reading the file in correctly, I also assigned another test variable and echoed that as part of the script. I tried sourcing /etc/profile and no luck.
I found a solution that works perfectly. I wasn't able to get it to work with ~/.bashrc, ~/.bash_profile, or ~/.ssh/rc but still not sure why it's not picking up my environment variables even with sourcing these.
Since it works when I manually ssh in and then run the commands one-by-one, I used these arguments to run ssh in a forced interactive login.
ssh server_B bash --login -i "~/perl/update.sh"
See these for more:
https://superuser.com/questions/564926/profile-is-not-loaded-when-using-ssh-ubuntu
https://unix.stackexchange.com/questions/46143/why-bash-unable-to-find-command-even-if-path-is-specified-properly
Hope this is useful for someone in the future. Thank you for your assistance Saigo.
I'm pretty decent with bash and UNIX commands, and the Terminal app, but I'm wondering, is there a way to make a "macro" (maybe that's the wrong word!) to automate some tasks?
For example, to get into my current project directory, I type:
$ cd ~/Documents/College/F13/CS362/lab3/os-lab-3
And then I immediately do
$ hg pull
(password)
And then
$ hg update
So is there a way to even automate that first step of the cd call? I've never tried anything like that before, not sure if what I'm going for is even possible.
Bonus: is there a way to have the macro enter my password when prompted as well? Security/privacy is not really an issue here, there's no thermonuclear codes hiding around in the repo.
The name generally used in this context (a macro in bash) is shell script. To automate the commands from your post you would need to create a file with a name like 'myscript.sh' with the following contents:
#!/bin/bash
cd ~/Documents/College/F13/CS362/lab3/os-lab-3
hg pull
hg update
The first line of the script is a hashbang. This is a special comment line which indicates that file should be executed using the indicated program. Bash in this case.
To run the script first ensure that it is executable by running the following command:
chmod +x myscript.sh
From there in terminal window just run the script by specifying the path to it:
./myscript.sh
Don't put passwords into shell scripts though! It is a bad habit. For authentication with Mercurial an ssh key pair is the best way to go. The ssh key can be loaded into OSX's keychain, so you won't have to type anything when you run the script. You'll also need to add the public portion of your ssh key pair to the list of authorized hosts on the remote Mercurial repository.
I tried activating a VirtualEnv through a shell script like the one below but it doesn't seem to work,
#!/bin/sh
source ~/.virtualenvs/pinax-env/bin/activate
I get the following error
$ sh virtualenv_activate.sh
virtualenv_activate.sh: 2: source: not found
but if I enter the same command on terminal it seems to work
$ source ~/.virtualenvs/pinax-env/bin/activate
(pinax-env)gautam#Aspirebuntu:$
So I changed the shell script to
#!/bin/bash
source ~/.virtualenvs/pinax-env/bin/activate
as suggested and used
$ bash virtualenv_activate.sh
gautam#Aspirebuntu:$
to run the script .
That doesn't throw an error but neither does that activate the virtual env
So any suggestion on how to solve this problem ?
PS : I am using Ubuntu 11.04
TLDR
Must run the .sh script with source instead of the script solely
source your-script.sh
and not
your-script.sh
Details
sh is not the same as bash (although some systems simply link sh to bash, so running sh actually runs bash). You can think of sh as a watered down version of bash. One thing that bash has that sh does not is the "source" command. This is why you're getting that error... source runs fine in your bash shell. But when you start your script using sh, you run the script in an shell in a subprocess. Since that script is running in sh, "source" is not found.
The solution is to run the script in bash instead. Change the first line to...
#!/bin/bash
Then run with...
./virtualenv_activate.sh
...or...
/bin/bash virtualenv_activate.sh
Edit:
If you want the activation of the virtualenv to change the shell that you call the script from, you need to use the "source" or "dot operator". This ensures that the script is run in the current shell (and therefore changes the current environment)...
source virtualenv_activate.sh
...or...
. virtualenv_activate.sh
As a side note, this is why virtualenv always says you need to use "source" to run it's activate script.
source is an builtin shell command in bash, and is not available in sh. If i remember correctly then virtual env does a lot of path and environment variables manipulation. Even running it as bash virtualenv_blah.sh wont work since this will simply create the environment inside the sub-shell.
Try . virtualenv_activate.sh or source virtualenv_activate.sh this basically gets the script to run in your current environment and all the environment variables modified by virtualenv's activate will be available.
HTH.
Edit: Here is a link that might help - http://ss64.com/bash/period.html
On Mac OS X your proposals seems not working.
I have done it this way. I'am not very happy with solution, but share it anyway here and hope, that maybe somebody will suggest the better one:
In activate.sh I have
echo 'source /Users/andi/.virtualenvs/data_science/bin/activate'
I give execution permissions by: chmod +x activate.sh
And I execute this way:
`./activate.sh`
Notice that there are paranthesis in form of ASCII code 96 = ` ( Grave accent )
For me best way work as below.
Create start-my-py-software.sh and pest below code
#!/bin/bash
source "/home/snippetbucket.com/source/AIML-Server-CloudPlatform/bin/activate"
python --version
python /home/snippetbucket.com/source/AIML-Server-CloudPlatform/main.py
Give file permission to run like below.
chmod +x start-my-py-software.sh
Now run like below
.start-my-py-software.sh
and that's it, start my python based server or any other code.
ubuntu #18.0
In my case, Ubuntu 16.04, the methods above didn't worked well or it needs much works.
I just made a link of 'activate' script file and copy it to home folder(or $PATH accessible folder) and renamed it simple one like 'actai'.
Then in a terminal, just call 'source actai'. It worked!