This question already has answers here:
Shell script current directory?
(7 answers)
Closed 2 years ago.
I want to be able to execute a bash script located in my home directory with the command ~/script_name.sh from any directory and then in the script, get the directory that it was ran from.
eg. I'm in the directory /foo/bar/baz, and execute /foo/script.sh, and it prints out /foo/bar/baz
pwd and $0/$BASH_SOURCE give me the directory my shell starts in and the path to the script in my home directory respectively.
Instead of invoking the external command pwd, consider using $PWD instead. If you want to protect against some rogue code having explicitly changed PWD, do a cd . (which is an internal command) first, which restores PWD to the correct value.
Related
This question already has answers here:
Difference between single and double quotes in Bash
(7 answers)
Closed 2 years ago.
I have an alias in bashrc that I use to generate a particular LaTeX document (the main command used is pdflatex) but I want to be able to execute it regardless of where I am. Unfortunately, it seems like you can't use use this command with an absolute path unless the path is 'under' your current directory, so I cd into the directory my .tex file is, run pdflatex, then try to cd back to my previous directory. In bashrc, I have my command as
alias nbr="cd ~/path/to/dir && pdflatex file.tex && cd $OLDPWD"
The command works fine outside of putting me back in my previous directory. For some reason, this command works perfectly fine in a regular bash shell, so I'm guessing there's some issue with what $OLDPWD is considered in the context of bashrc but I'm not sure. Any ideas?
#Cyrus's answer fixed it...should've used single quotes.
This question already has answers here:
Why do you need ./ (dot-slash) before executable or script name to run it in bash?
(9 answers)
Closed 4 years ago.
Our class on unix had an a question I did not know the answer to.
"why is it necessary to use ./XXX.sh to execute a bash executable?". I have not been able to find the answer on the web or in our textbook.
When you are invoking a command, the shell looks for the command in your $PATH variable, it will not look into your current directory. So you have to specifically tell the shell where your command is located. In this case, when the command or script is located in your current directory ., you need to invoke it using ./XXX.sh. In fact you can invoke scripts not inside your current directory using its full path e.g. /some/path/XXX.sh or relative to your current working directory e.g. ../../some/path/XXX.sh
This question already has answers here:
Why can't I change directories using "cd" in a script?
(33 answers)
Closed 5 years ago.
I have this script in a file called /Users/tcl/scripts/gotoroot:
echo "hello"
cd /
echo "good bye"
But when I run it I get this:
User:scripts tcl$ pwd
/Users/tcl/scripts
User:scripts tcl$ gotoroot
hello
good bye
User:scripts tcl$ pwd
/Users/tcl/scripts
User:scripts tcl$
The directory has not changed and I don't know why? It should be /, not /Users/tcl/scripts
When you run the script, it starts a subshell in a new process. The cd changes directory inside that subshell, not inside your terminal process.
Test it out by putting this in your script:
pwd
cd /
pwd
You should see that it changes to / inside the script.
Shell scripts are run inside of sub processes. The CD is working but it's happening inside a different process than your main terminal session and has no effect on the working directory once you return to your terminal session.
This question already has answers here:
Why do you need ./ (dot-slash) before executable or script name to run it in bash?
(9 answers)
Closed 5 years ago.
When I executeinit-hooks I get
bash: init-hooks: command-not found
here are the contents of init-hooks:
#!/bin/bash
set -e
printf '\ncopying hooks\n\n'
cp ./hooks/* ../../.git/hooks
When I execute cp ./hooks/* ../../.git/hooks from bash directly execution is successful.
(note this is the same command as what is in the script)
Proof of the files are in the directory and the results of execution:
Why does my script behave differently than the command/why is my script not found?
On the Linux systems (where bash comes from) the current directory is usually not included in the path for security reasons.
Run echo $PATH to check what directories are used to search for executables when they are provided in the command line without a path. The current directory (.) should not be there.
Run the script as ./init-hooks and bash will find it.
I suugest to run it following way
./init_hooks
or put fully qualified file name.
make sure to make the script executable
chmod +x ./init_hooks
This question already has answers here:
Why do you need ./ (dot-slash) before executable or script name to run it in bash?
(9 answers)
Closed 9 years ago.
To be more specific, what I mean is:
Suppose I have a python script called test.py with a proper shebang on the first line, say
#!/usr/bin/env python
print 'this works'
In the shell, when I type:
$ test.py
Nothing happens, but when I type:
$ ./test.py
The command is invoked and prints "this works".
Why is that? I thought "." just meant the current directory. Why would having a ./ suddenly mean we want to execute whatever comes next? Thanks.
The shell only looks for executables in the path (try echo $PATH in the shell to see its value). If . is not in the path, you'll have to give the explicit path to the executable. Not having . in the path is a good idea: imagine somebody managed to put an executable named ls in your home directory!
Because the current directory (where you had saved test.py) is not in your $PATH environment variable.
$PATH is searched for executables when you try to run one.