Is it possible to execute a command relative to a Terminal shell script? - osx-lion

I have a Terminal shell script file start.command that I launch from finder with:
ls -l
The file is in ~/foo but list ~, can I get the path of it's containing dir. I'd like to launch an application that is in the same folder as the file when the user runs the .command but it seems like I would need the absolute path to the file for that to work.

Assuming bash, you need to cd to the script's enclosing directory before running ls.
You can one-line it with this:
cd "$(dirname "$0")"
$0 is the script's relative path, i.e. whatever you used on the command line to invoke it. dirname strips the filename from the path.
$() is a value expansion to feed to cd, and the quotes are all necessary to handle things like spaces in paths.

Related

Move file with a dash

I move file using Midnight Commander to file with name "-name.csv". But 'mc' thinks I use option. Why is this happening? And how I can move to file with name like "-name.csv".
desktop:~/s$ mv name.csv "-name.csv"
mv: invalid option -- 'a'
It's not mc, it's mv. Quoting doesn't help because the quotes are interpreted by the shell so mv receives unquoted parameters name.csv and -name.csv. You need to hide the dash so that option parser in mv stops thinking it's an option. Use relative path ./ for the current directory, or full path:
mv name.csv ./-name.csv
mv name.csv "`pwd`"/-name.csv

How can I make a function run every time cd successfully changes to another directory within sh on FreeBSD?

I'm using sh as my shell on FreeBSD but I want to be able to have a pretty prompt like the one bash gives me on Ubuntu. There are two things that the FreeBSD implementation of sh seems to lack as far as PS1 escape characters go:
The \w works but does not expand $HOME to ~, so this is something I have already hacked up myself
I can use PS1 to update the prompt on the terminal, but as far as I can tell it is not possible to use the PS1 variable to update the title bar as well. ESC and BEL fail to set the title as one would expect if they were using bash or ksh
Here is my .shrc file
update_prompt() {
case "$PWD" in
"$HOME"*)
pretty_pwd="~${PWD#*"${HOME}"}"
;;
"/usr$HOME"*)
pretty_pwd="~${PWD#*"/usr${HOME}"}"
;;
*)
pretty_pwd="$PWD"
;;
esac
case "$TERM" in
xterm*|rxvt*)
PS1="[$USER#\\h $pretty_pwd]\\$ "
;;
*)
;;
esac
printf "\\033]0;[%s#$(hostname -s): %s]\\007" "$USER" "$pretty_pwd"
}
update_prompt
So when I fire up a terminal or log in via ssh, it gives the pretty prompt that I like. But now I need this function to run every time that cd is executed and returns an exit status of 0.
I was going to use an alias that was something like:
alias cd="cd $1 && update_prompt"
but that was before I realized that aliases do not except arguments. How might I go about doing something like this?
You can use a function instead of an alias:
cd() {
command cd "$#" && update_prompt
}
Just put it into ~/.shrc. You have to use command here to let sh know that you are referring to the actual cd builtin command instead of the function you've just defined.
Refer to the sh(1) manual page for the details on how to make sh(1) source the ~/.shrc file when it starts:
Therefore, a user should place commands that are to be executed only at login
time in the .profile file, and commands that are executed for every shell
inside the ENV file. The user can set the ENV variable to some file by placing
the following line in the file .profile in the home directory, substituting for
.shrc the filename desired:
ENV=$HOME/.shrc; export ENV
I use this trick in my cd alias manager. Here's a link to the source code of the function: https://github.com/0mp/goat/blob/v2.5.0/libgoat.sh#L31-L57
You can do it with alias+arguments if you swap the commands:
$ alias cd="echo change; cd"
$ pwd
/nas
$ cd /
change
$ pwd
/
$ cd /etc
change
$ pwd
/etc
$

Can a Fish script tell what directory it's stored in?

So, I really like Fish - but I need some help with scripting.
and in particular finding the path of the script being run.
Here is the solution for BASH
Getting the source directory of a Bash script from within
Can anyone help me find the equivalent with fish?
status --current-filename will output the path to the currently executing script.
For more information on the status command, you can run man status or see the documentation at http://fishshell.com/docs/current/commands.html#status
In fish shell,
set DIR (cd (dirname (status -f)); and pwd)
is an equivalent to the BASH one liner
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
mentioned in Can a Bash script tell what directory it's stored in?.
NOTE: fish shell will cd into that dir and stay there. Bash will cd but it stays contained in subcommand.
File path
To get the full path of the script, use status --current-filename, or
set FILE (status --current-filename) to declare a variable.
Directory path
To get the full path to the directory the script is stored in, use dirname (status --current-filename), or set DIR (dirname (status --current-filename)) to declare a variable.
The equivalent to this question is the following:
set DIR (dirname (status --current-filename)) is the equivalent
Since readlink -m does not exist on macOS,
DIR=dirname (realpath (status -f))
Works on macOS and Linux at the same time.
This solution also has the benefit to work from an .sh file or even the command line.

Running a script in bash

I have a script in one of my application folders.Usually I just cd into that locatin in Unix box and run the script e.g.
UNIX> cd My\Folder\
My\Folder> MyScript
This prints the required result.
I am not sure how do I do this in Bash script.I have done the following
#!/bin/bash
mydir=My\Folder\
cd $mydir
echo $(pwd)
This basically puts me in the right folder to run the required script . But I am not sure how to run the script in the code?
If you can call MyScript (as opposed to ./MyScript), obviously the current directory (".") is part of your PATH. (Which, by the way, isn't a good idea.)
That means you can call MyScript in your script just like that:
#!/bin/bash
mydir=My/Folder/
cd $mydir
echo $(pwd)
MyScript
As I said, ./MyScript would be better (not as ambiguous). See Michael Wild's comment about directory separators.
Generally speaking, Bash considers everything that does not resolve to a builtin keyword (like if, while, do etc.) as a call to an executable or script (*) located somewhere in your PATH. It will check each directory in the PATH, in turn, for a so-named executable / script, and execute the first one it finds (which might or might not be the MyScript you are intending to run). That's why specifying that you mean the very MyScript in this directory (./) is the better choice.
(*): Unless, of course, there is a function of that name defined.
#!/bin/bash
mydir=My/Folder/
cd $mydir
echo $(pwd)
MyScript
I would rather put the name in quotes. This makes it easier to read and save against mistakes.
#!/bin/bash
mydir="My Folder"
cd "$mydir"
echo $(pwd)
./MyScript
Your nickname says it all ;-)
When a command is entered at the prompt that doesn't contain a /, Bash first checks whether it is a alias or a function. Then it checks whether it is a built-in command, and only then it starts searching on the PATH. This is a shell variable that contains a list of directories to search for commands. It appears that in your case . (i.e. the current directory) is in the PATH, which is generally considered to be a pretty bad idea.
If the command contains a /, no look-up in the PATH is performed. Instead an exact match is required. If starting with a / it is an absolute path, and the file must exist. Otherwise it is a relative path, and the file must exist relative to the current working directory.
So, you have two acceptable options:
Put your script in some directory that is on your PATH. Alternatively, add the directory containing the script to the PATH variable.
Use an absolute or relative path to invoke your script.

finding a files path in the command line

I am doing a batch scripting assignment where I have to call one script from inside another. I need the script to run the second script no matter where my lecturer saves these scripts. How would I do this. Is there some way to find the path of script inside the script and use that to execute the file. Any help would be great. I think I need to use %'s but i'm not sure.
The name of the script is Hello World.bat.
How would I copy Hello World.bat to the C:\ if I don't know which directory the lecturer has placed it in. what command/s would I use so that the copy would work regardless of the scripts location.
I don't see the "DOS" tag, but I'll assume that it is for now. If you want the entire path, you can get it by doing this:
echo %cd%
If you want just the last folder, this works (inside a .bat file):
for %%* in (.) do #echo %%~n*
Note that from the command line, the above command will work with single %'s:
for %* in (.) do #echo %~n*
If the script you are executing is calling other scripts in the SAME folder location, you can prefix the path statement with "%~dp0" or "%~dps0" but do not put a backslash between that and the name of the script you are calling. In other words, if script1.bat is calling script2.bat in the same folder, the statement in script1.bat would refer to "%~dp0script2.bat"
sorry about batch files, am not familiar, but in nix shell, there is the locate command which can return the path of the file , if you know the filename exactly and the name is unique.
like
name=$(locate filname)