Questions tagged [shebang]
Use the tag /shebang if your question is about `#!`-string at the beginning of a script
112
questions
-1
votes
2answers
74 views
Can duplication of POSIX shebang (#!/bin/sh) when sourcing files into one piece cause problems, be it practical or in theory?
I recently started to develop my Linux POSIX shell scripts in a more structured way.
Let me explain:
Code [A] is being sourced by some code [B], just some minimal example:
#!/bin/sh
# REQUIREMENTS
# ...
3
votes
2answers
124 views
FreeBSD shebang error
I would like to put shebang #!/bin/sh -eufo pipefail in my script. But there're several things strange:
The script would fail with that shebang in FreeBSD but not when run on MacOS
on FreeBSd, the ...
-2
votes
2answers
470 views
What does the `-eu` mean in `#!/bin/bash -eu` at the top of a bash script? (or any of `-abefhkmnptuvxBCHP`)
What does the eu mean after #!/bin/bash -eu at the top of a bash script?
Normally I begin my bash scripts with this hashbang/shebang:
#!/bin/bash
but I just came across one with
#!/bin/bash -eu
and ...
0
votes
2answers
157 views
Fix path used by shebang #!/usr/bin/perl and #!/usr/local/cpanel/3rdparty/bin/perl
I can't find anyone that can help me fix this issue. after a recent centos update my CGI scrips that use:
#!/usr/local/cpanel/3rdparty/bin/perl
or
#!/usr/bin/perl
are trying to use an old perl ...
0
votes
1answer
107 views
How do I know if my Python script has been called with the interpreter on the command line or as an executable (via shebang)?
Is there a way in a Python script to determine if the caller provided the interpreter on the command line or if the shebang line was used to determine the interpreter to use?
As a simple example, ...
1
vote
2answers
61 views
Why does a shebang script run as init= have an euid of 0 when run from an initrd, but not otherwise?
I am trying to create my own PID 1 init script, to be called from the boot cmdline with init=/myscript. How can I make it work on a real filesystem, with any kernel?
When it runs in an initrd, it ...
0
votes
1answer
272 views
Why would anyone use sh instead of bash? [closed]
I have to modify existing shell scripts and they start with
#!/bin/sh
What reason would someone use that on a system that also supports bash?
I am tempted to change it but I want to make sure there'...
1
vote
1answer
2k views
/bin/env : bad interpreter
I am on Linux Mint 19.03.
I have a setup shell script file, setup.sh. When I run ./setup.sh
muyustan@mint:~/Downloads/quartusExtracted$ ./setup.sh
bash: ./setup.sh: /bin/env: bad interpreter: No ...
0
votes
1answer
61 views
Ways for making a Scala script standalone in Linux?
Programming Scala says:
Invoking scripts with scala is tedious when you use these scripts
frequently. On Windows and Unix-like systems, you can create
standalone Scala scripts that donāt ...
3
votes
2answers
106 views
Pass options to AWK script bypassing AWK
Can I get arguments that happen to be AWK options passed directly to a pure AWK script?
Example script:
#!/usr/bin/env -S awk -f
BEGIN { if (ARGV[1] == "-h") print "whoop" }
I want ./myscript -h to ...
0
votes
1answer
46 views
/usr/bin/env python runs on cmdline, fails in #! line [duplicate]
I'm trying to make a python script runnable, by adding the following "shebang" first line:
#!/usr/bin/env python
but when I run the file, I get:
$ myscript.py
: No such file or directory
Now, if I ...
9
votes
1answer
2k views
POSIX shell scripts shebang #!/bin/sh vs #!/usr/bin/env sh, any difference?
I recently noticed that many scripts are using /usr/bin/env in their shebang. I have seen that mainly using Bash and Python, but thus far never in conjunction with POSIX sh (ash, dash,...).
I wonder ...
1
vote
1answer
8k views
/bin/ksh: bad interpreter: No such file or directory [duplicate]
I have script with #!/bin/ksh in the first line.
When I try to execute this script (run ./myscript.sh) the error occurred:
-bash: ./myscript.sh: /bin/ksh: bad interpreter: No such file or directory
...
0
votes
0answers
244 views
sh -c in shebang [duplicate]
I have a file test with the content
#!/bin/sh -c 'echo was called with $0'
I if i execute it it with ./test, i would expect the OS to effectively execute
sh -c 'echo was called with $0' ./test
...
2
votes
1answer
3k views
Invalid option name error with shebang “#!/bin/bash -o pipefail” in script [duplicate]
I have a file named test.sh:
#!/bin/bash -o pipefail
echo "Running test"
git diff HEAD^ HEAD -M --summary |
grep delete |
cut --delimiter=' ' -f 5
When I try to run this script as:
./test.sh
I ...
1
vote
1answer
217 views
Python script shebang behavior
I have a python script, in which I have the following shebang #!/usr/bin/python
the script permissions are -rwxrwxrwx. 1 user user 709 script.py the owner of the script is the same as the user I use ...
0
votes
1answer
423 views
Set default interpreter in fish shell
I've installed mill on arch linux with fish as my default shell. Since the file /usr/bin/mill doesn't start with a shebang, fish won't execute the file. Instead it responds with
$ mill
Failed to ...
0
votes
2answers
101 views
Why does second part of shebang have a priority?
I have python script running under different python executable than default one.
I have python executables both in /usr/bin and in /mydir/mybins.
If I run, I get:
$which python
/usr/bin/python
And ...
4
votes
6answers
4k views
shebang or not shebang
I want to use a program in the shebang, so I create a script named <myscript> with:
#!<mypgm>
I also want to be able to run <mypgm> directly from the command prompt.
<mypgm> ...
4
votes
3answers
307 views
Who runs the interpreter for files that are execute-only?
If the current user only has execute (--x) permissions on a file, under which user does the interpreter (specified by #!/path/to/interpreter at the beginning of the file) run?
It couldn't be the ...
14
votes
6answers
5k views
Is it correct to use /bin/sh in the hashbang if the Bourne shell isn't available in a distribution?
Generally, shell scripts contain the following comment at the first line of the script file: #!/bin/sh. According to the researches that I made, this is called "hash bang" and it is conventional ...
18
votes
3answers
2k views
Why is the behavior of the `#!` syntax unspecified by POSIX?
From the Shell Command Language page of the POSIX specification:
If the first line of a file of shell commands starts with the characters "#!", the results are unspecified.
Why is the behavior of #...
17
votes
2answers
1k views
How does this shebang that starts with a double hyphen (--) work?
I have found the following kind of shebang in the RosettaCode page:
--() { :; }; exec db2 -txf "$0"
It works for Db2, and a similar thing for Postgres. However, I do not understand the whole line.
...
1
vote
1answer
118 views
Why does a script without she-bang can be run? [duplicate]
As far as I understand, to make kernel execve a non-ELF file, the file must be a script started with a she-bang #!, but I have a script run successfully without it, why does this happen?
xtricmanā...
1
vote
5answers
879 views
Separate environment with different /bin/sh
I have a bunch of shell scripts which incorrectly assume /bin/sh to be equivalent to /bin/bash. E.g., they have the #!/bin/sh shebang, but use the source command instead of . (dot).
I run Ubuntu 16, ...
3
votes
0answers
335 views
Why do I need this shebang? [duplicate]
perldoc perlrun contains this example:
#!/bin/sh
#! -*-perl-*-
eval 'exec perl -x -wS $0 ${1+"$@"}'
if 0;
But I don't understand why it might be needed.
For example, if my perl interpreter ...
1
vote
2answers
122 views
Why does shebang lead to a different process name than an explicit call?
Summary
Using mirage as an example, a python program that begins with a shebang:
#!/usr/bin/python
...
Looking at /proc/<pid>/comm or using pgrep, it appears like ...
... the process name ...
13
votes
3answers
3k views
Why doesn't “ps ax” find a running bash script without the “#!” header?
When I run this script, intended to run until killed...
# foo.sh
while true; do sleep 1; done
...I'm not able to find it using ps ax:
>./foo.sh
// In a separate shell:
>ps ax | grep foo.sh
...
1
vote
0answers
134 views
Upstart script with expect scripting
Please give me advices about expect scripting combined with an upstart script.
There are 3 scripts that I am dealing with right now.
Script A) Java program
PATH: /opt/~~/manager
Script B) ...
0
votes
1answer
477 views
Run python script without declare it interpreter
I have such a program to check methods of data from the command line:
me at me in ~/Desktop/Coding/codes
$ cat check_methods.py
#! /usr/bin/env python
from sys import argv
methods = dir(eval(argv[1]))...
2
votes
1answer
730 views
How is a bash script executed via its filename as command name with and without shebang?
From bash manual:
3.7.2 Command Search and Execution
After a command has been split into words, if it results in a simple
command and an optional list of arguments, the following actions are
...
1
vote
1answer
1k views
/usr/bin/env: āawk -fā: No such file or directory [duplicate]
Linux shylock-archinux 4.15.15-1-ARCH #1 SMP PREEMPT Sat Mar 31 23:59:25 UTC 2018 x86_64 GNU/Linux
My machine is above.Anyone know what happend?
The script with shebang #! /usr/bin/env awk -f don't ...
2
votes
2answers
76 views
How shall I allow more than one arguments to the interpreter in a shebang in a script
From Glenn's reply:
Read your execve(2) man page. The limitation on a single optional
argument is OS dependent. Linux treats all words after the interpreter
as one single argument
If you ...
1
vote
1answer
283 views
Basic usage of /etc/cron/ (d): correct pattern for /etc/cron (daily/weekly/monthly)
I use Ubuntu 16.04 with Bash and I've created this extensionless, shebangless file /etc/cron.daily/cron_daily:
for dir in "$drt"/*/; do
if pushd "$dir"; then
wp plugin update --all --allow-root
wp ...
3
votes
2answers
2k views
What are the pro's and con's in using the “-l” in a script shebang
I recently came up to an easy fix for a crontab logging issue and I am wondering what are the pro's and con's of using this specific fix (running a script with a "login shell flag"), as:
#!/bin/bash -...
12
votes
6answers
2k views
Too many shebang (script declaration) lines — any way to reduce their amount?
I have a project comprised of about 20 small .sh files. I name these "small" because generally, no file has more than 20 lines of code. I took a modular approach because thus I'm loyal to the Unix ...
0
votes
0answers
892 views
shebang and command parameters [duplicate]
I tried to pass parameters to bash in shebang of executable script:
#! /usr/bin/env bash -ex
false
But I get an error:
/usr/bin/env: ābash -exā: No such file or directory
Should I avoid to use /...
2
votes
1answer
328 views
cannot get scripts to run in a Lubuntu (Xenial) Minimal (+LXDE) VM with shebangs
I embarrassed myself a little here with a simple typo and a profound ignorance. Save yourself some grief:
your hasbangs/shebangs must always have a leading /, such as #!/bin/bash
be precise
if you ...
6
votes
6answers
1k views
Fastest way to determine if shebang is present
If I have a file with
#!/usr/bin/env foobar
what is the fastest/best way to determine if this file has a hashbang? I hear you can just read the first 2 bytes? How?
9
votes
3answers
2k views
Can I use a variable content as a shebang? [closed]
I have a shell script in which I want to add a shebang.
Given a variable defined as follows:
SHEBANG="#!/bin/sh"
My question is if I can use that variable in another script like this:
$SHEBANG
# ...
1
vote
1answer
353 views
Change the default executable for file with potentially missing shebang
I have a library - users are to create executable files, potentially with a hashbang to tell exec which executable to use. If they omit the hashbang, then I think most systems default to /bin/sh, I ...
0
votes
1answer
480 views
#!/usr/bin/env foo #!vs /usr/bin/foo [duplicate]
Which of the above forms is "better" for running bash, python etc. scripts? Why can't I just do #!$(which foo)? Is it neccecery to specify full path to env? I gather from this answer, that the path /...
3
votes
2answers
862 views
xslt shbang: Using xslt from the command line
I have (foolishly?) written a couple of moderately general-purpose xslt
scripts.
I'd quite like to turn these into executables that read an xml document from standard in or similar.
The way you do ...
59
votes
7answers
20k views
Multiple arguments in shebang
I am wondering whether there is a general way of passing multiple options to an executable via the shebang line (#!).
I use NixOS, and the first part of the shebang in any script I write is usually /...
0
votes
2answers
358 views
What is the actual command executed when running a script with a shebang as its name with same arguments?
From bash manual about shebang
Most versions of Unix make this a part of the operating systemās
command execution mechanism. If the first line of a script begins with
the two charactersā #!ā, ...
2
votes
1answer
1k views
Avoid passing environment variable to python script
I have a small python script
#!/usr/bin/env python3
import some_python3_module
def main():
# do stuff
if __name__ == '__main__':
main()
and cannot run this script with Python3, since ROS ...
2
votes
1answer
473 views
Multiple arguments in shebang lines
Linux only supports one argument in a shebang line:
This:
#!/bin/sh
cat > pr_args <<'EOF'
#!/bin/sh -e
printf "'%s'\n" "$@"
EOF
cat > shebang <<'EOF'
#!pr_args a b c
EOF
chmod +x ...
2
votes
1answer
275 views
validity check all files in a folder depending on the shebang [closed]
I have a project with some lua and some bash files. I want to loop over all files and depending on the shebang I want to execute a validity check.
22
votes
3answers
9k views
Which shell interpreter runs a script with no shebang?
Suppose the default shell for my account is zsh but I opened the terminal and fired up bash and executed a script named prac002.sh, which shell interpreter would be used to execute the script, zsh or ...
17
votes
6answers
6k views
Choose interpreter after script start e.g. if/else inside hashbang
Is there any way to dynamically choose the interpreter that's executing a script? I have a script that I'm running on two different systems, and the interpreter I want to use is located in different ...
