I am getting confused about Linux shells. It may be that I oversee something obvious as a Linux noob.
All I want is the following script to run:
#!/bin/bash
echo "Type some Text:"
read var
echo "You entered: "$var
Here is the situation:
Installed Ubuntu Server 14.04 in a VirtualBox on windows
Installed it with this packages
A SAMBA mounted on /media/buff
The script is on /media/buff/ShellScript/test.sh
made executable by "sudo chmod a+x /media/buff/ShellScript/test.sh"
The rest is default
I am using PSPad on windows to edit the script file
I read about the dash but I'm not getting it.
Here are some variations:
Using sh to launch
user#Ubuntu:/media/buff/ShellScript$ sh test.sh
Type some Text:
:bad variable nameread var
You entered:
Using bash to launch:
user#Ubuntu:/media/buff/ShellScript$ bash test.sh
Type some Text:
': Ist kein gültiger Bezeichner.var (means no valid identifyier)
You entered:
Changed the Shebang in the script to "#!/bin/sh", Using sh to launch
user#Ubuntu:/media/buff/ShellScript$ sh test.sh
Type some Text:
:bad variable nameread var
You entered:
I searched across the Internet for hours now and I assume, that the script itself is ok, but there are missing some environment settings.
I used "sudo dpkg-reconfigure dash" to set dash as default shell (which I think is ubuntu default anyway)
sadface panda :)
There are most probably carriage returns (CR, '\r') at the end of your lines in the shell script, so the variable is trying to be read into var\r instead of var. This is why your error message is meaningless. A similar error should look like this:
run.sh: 3: export: [... the variable name]: bad variable name
In your case bash throws an error because var\r is illegal for a variable name due to the carriage return, so it prints
test.sh: 3: read: var\r: bad variable name
but the \r jumps to the beginning of the line, overwriting the start of the error message.
Remove the carriage returns fom the ends of lines, possibly by using the dos2unix utility.
Here are a list of editors that support unix newline character.
Brackets has an extension for new-line/end-of-line support and it is built-in in Notepad++. Go to the 'Edit' tab. Find 'EOL Conversions' and select Unix (LF).
That should get it done.
Related
I am a beginner of bash. I encounter a problem like this:
$ "make -p"
when I type the above in bash command line, there is nothing to happen, no error, no result msg.
I have searched double quotes syntax of bash in many websites. All of these materials give similar interpretation as below:
https://www.gnu.org/software/bash/manual/html_node/Double-Quotes.html
and give examples like:
echo "argument"
I do not find something like "echo argument". Moreover, I find a strange difference between bash command line and bash scripts.
If I type a non-existing command in command line:
$ "holy shit"
$ "look that"
there is nothing to happen. But if I type it in bash scripts:
#!/bin/bash
"holy shit"
"look that"
and execute this script, an error msg will be throw out:
$ ./myshell
./myshell: line 2: holy shit: command not found
./myshell: line 3: look that: command not found
Would someone can help give a detailed interpretation about the effect of double quotes when they enclosed the whole command?
Why there is no output in command-line?
Why it is different between command line and scripts?
If you enter a command foo, the shell searches the directories listed in your PATH variable until it finds a command of this name. If there is none, you get the error message command not found.
If you enter a command, which contains at least one slash - for example ./foo or foo/bar -, the shell does not search the PATH, but assumes that you have already entered the correct path to your command. If it does not exist, you get the error message No such file or directory.
In your case,
"cd home"
searches for a file with name cd home somewhere along your PATH, but there is no file of this name, and you get command not found. If you enter
"cd /home"
the shell bypasses PATH-search and assumes, that there exists a directory named cd (i.e. the 3 letters c,d,space) in your current directory, and below it a file named home, with x-bit set. There is no such file (and no such directory) on your system, and you get the error message No such file or directory.
If you are in the mood of experimenting around, you could try the following:
mydir="cd "
mkdir "$mydir"
echo "echo Hello Stranger" >"$mydir/home"
chmod +x "$mydir/home"
"cd /home"
This should print Hello Stranger. Pay attention that in the assignment to mydir, there must be a single space between the cd and the closing quote.
The double quotes mean it is a string. You can do something like:
echo "Hello everybody"
either at the command line or the shell. Sometimes when people put stuff in quotes. you are supposed to replace what is in quotes with your own variable (removing the quotes), and sometimes people put quotes around the whole command you are supposed to type to show the what exactly you should type. For your example of "make -p" just type it without the quotes and it should work in both the command line and as a script.
I have a bash script in which I define the below function,
function start-if-exists()
{
if [ "`docker container ls -a|grep $1`" ]; then
echo "Container $1 exists. Starting $1..."
return `docker start $1`
else
echo "Container $1 doesn't exists."
return ""
fi
}
While executing the above function in terminal(zsh) directly I am not getting any error. But when I execute it using sh command(sh my_script.sh), I am getting the below error.
my_script.sh: line 10: `start-if-exists': not a valid identifier
where my_script.sh is the name of file.
What am I missing that my script works with zsh but fails in sh?
/bin/sh is bash, but, when started as /bin/sh, it starts in POSIX mode. According to the bash man page, in POSIX mode:
Function names must be valid shell `name's. That is, they may not
contain characters other than letters, digits, and underscores, and
may not start with a digit. Declaring a function with an invalid
name causes a fatal syntax error in non-interactive shells.
A note about how to figure things like this out:
At the Terminal command line, I executed /bin/sh --version to see information about it. It printed “GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin17)”.
Then I referred to the bash man page, using the command man bash. Since that is long, you might prefer to save a copy to a file and view it in your preferred text editor. The raw man output includes archaic underscores and backspaces. You can get a copy without these by executing man bash | col -b > file.txt.
In the man page, I searched for ”sh” (as a complete word, not a raw search for those letters, since they appear as parts of many unrelated words). This quickly revealed discussion that bash behaves differently when started as “sh”; it starts in POSIX mode.
Searching further for “POSIX” revealed a list of things that are different in POSIX mode.
I am trying to create an AppleScript with commands below. An issue I am having is there is an error at the third line. I have no problem using the lame command in the terminal directly. In addition, lame is not a native Mac utility; I installed it on my own. Does anybody have a solution?
do shell script "cd ~/Downloads"
do shell script "say -f ~/Downloads/RE.txt -o ~/Downloads/recording.aiff"
do shell script "lame -m m ~/Downloads/recording.aiff ~/Downloads/recording.mp3"
-- error "sh: lame: command not found" number 127
do shell script "rm recording.aiff RE.txt"
To complement Paul R's helpful answer:
The thing to note is that do shell script - regrettably - does NOT see the same $PATH as shells created by Terminal.app - a notable absence is /usr/local/bin.
On my OS X 10.9.3 system, running do shell script "echo $PATH" yields merely:
/usr/bin:/bin:/usr/sbin:/sbin
There are various ways around this:
Use the full path to executables, as in Paul's solution.
Manually prepend/append /usr/local/bin, where many non-system executables live, to the $PATH - worth considering if you invoke multiple executables in a single do shell script command; e.g.:
do shell script "export PATH=\"/usr/local/bin:$PATH\"
cd ~/Downloads
say -f ~/Downloads/RE.txt -o ~/Downloads/recording.aiff
lame -m m ~/Downloads/recording.aiff ~/Downloads/recording.mp3
rm recording.aiff RE.txt"
Note how the above use a single do shell script command with multiple commands in a single string - commands can be separated by newlines or, if on the same line, with ;.
This is more efficient than multiple invocations, though adding error handling both inside the script code and around the do shell script command is advisable.
To get the same $PATH that interactive shells see (except additions made in your bash profile), you can invoke eval $(/usr/libexec/path_helper -s); as the first statement in your command string.
Other important considerations with do shell script:
bash is invoked as sh, which results in changes in behavior, most notably:
process substitution (<(...)) is not available
echo by default accepts no options and interprets escape sequences such as \n.
other, subtle changes in behavior; see http://www.gnu.org/software/bash/manual/html_node/Bash-POSIX-Mode.html
You could address these issues manually by prepending shopt -uo posix; shopt -u xpg_echo; to your command string.
The locale is set to the generic "C" locale instead of to your system's; to fix that, manually prepend export LANG='" & user locale of (system info) & ".UTF-8' to your command string.
No startup files (profiles) are read; this is not surprising, because the shell created is a noninteractive (non-login) shell, but sometimes it's handy to load one's profile by manually by prepending . ~/.bash_profile to the command string; note, however, that this makes your AppleScript less portable.
do shell script command reference: http://developer.apple.com/library/mac/#technotes/tn2065/_index.html
Probably a PATH problem - use the full path for lame, e.g.
do shell script "/usr/local/bin/lame -m m ~/Downloads/recording.aiff ~/Downloads/recording.mp3"
I have been struggling to get the path of an installed BASH command via Applescript for a long time. Using the information here, I finally succeeded.
tell me to set sox_path to (do shell script "eval $(/usr/libexec/path_helper -s); which sox")
Thanks.
Url：http://sourceforge.net/project/showfiles.php?group_id=290&package_id=309
./configure
make install
I'm trying to execute a very simple script with cygwin, composed of:
#!/bin/bash\n
echo "hi"\n
with cygwinpath\bin\bash.exe /cygdrive/c/my_path/test.bash
but it says
/cygdrive/c/my_path/test.bash: line 1: #!/bin/bash: No such file or directory
However, it still prints 'hi'.
Why is this, and how to fix it ?
Thanks.
The first line of your script should just be #!/bin/bash and not #!/bin/bash\n
The code is still executing because the heading #!/bin/bash specifies a shell, and echo "hi"\n is a command to the terminal.
As for your issue I'm having no problems running it using the following path in the cygwin terminal:
/cygdrive/c/<my_path>/bin/bash.exe /home/user/test.bash
I am trying to run my shell script from command line lets say;
my script looks like this:
#!bin/bash
echo hello
When try to run this source ./abcd.sh I get this error.
"' is not a typo you can run the following command to lookup the package that contains the binary:
command-not-found
: command not found
hello
"
Never seen this before something wrong with having a empty line before "echo hello" ? I was wondering if anyone else encountered something like this.
Along with the first line of your script being a comment, it sounds like your file has DOS line endings, and the carriage return is being treated as the command that isn't found. The error message sounds like something provided by a custom command_not_found_handle function (which I believe Ubuntu defines).
#!bin/bash
needs to be
#!/bin/bash
or wherever bash is installed (you can locate this by doing whereis bash).
Your program should work fine when invoked using bash, i.e., bash ./abcd.sh, but when executed directly ./abcd.sh then the hashbang line does matter because that is how the interpreter is located for the script contained in the executable file.
Try echo 'hello', within quotes. It looks like there is a newline between the echo command and hello and it is trying to run 'hello' as a command.
The hashbang line should be #!/bin/bash, but messing that up won't matter as it will interpret any line that starts with a hash as a comment.
Run script with debug option to see which line actually is failing:
bash -x abcd.sh
Note: in this case the Shebang line will be treated as a comment, so if the rest of your script is correct, it will execute correctly:
$ bash -x abcd.sh
+ echo hello
hello
Make sure your file does not have a BOM
I had the same problem when editing a script under Windows with Notepad++.
make sure to convert to "UTF-8 witout BOM".