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-4
votes
2answers
49 views

How do I print all env vars beginning with the letter 'T'?

This was an exercise for a course I'm on and I got really stuck at frustrated. I think my main problem is I keep putting the ">>" the wrong way round and then getting stuck in an editor which I don't ...
5
votes
2answers
58 views

Introduction of env --null

I have tried to extract environment variables in a Python process with help of env --null, which works even for environment variables containing newline character. But on some machines I have ...
1
vote
2answers
27 views

Why is $COLUMNS not listed by either env or set? (on zsh)

I can $ echo $COLUMNS 95 and get a result, but if I env | grep COLUMNS or set | grep COLUMNS I get nothing. (Update: I just discovered that the behavior is different on bash. I'm using ...
13
votes
1answer
256 views

Is there a difference between prepending a name-value-pair to a command and using env in bash?

Let's say I invoke A=B command and env A=B command in bash. Is there any situation where there might be a difference between both invokations?
2
votes
3answers
546 views

Upstart - load bashrc variable

I'm wondering how to load bashrc variables in an upstart script and run (node.js in that case server). What is the best way to do it? I tried this: exec sudo -u someuser $NODE_PATH ...
2
votes
0answers
348 views

Reading from /etc/environment with sudo

Using Ubuntu 14.04 LTS, I'm having a problem trying to read environment variables from /etc/environment when using sudo env. Basically, they are not being displayed. When I do just env, these ...
0
votes
1answer
67 views

Is there a command which displays options like `errexit` and `braceexpand` other than `help set`?

If you type help set, then - among other things - a list of shell options is displayed. But these options are not the same as those displayed with shopt. And different also from those displayed with ...
1
vote
2answers
69 views

Toggle/macro/xargs-like thing for shell variables

So I'm stuck doing a lot of cross-compiling and am typing stuff like this a lot FOO=bar command --some-args BAZ=qxt other-command --other-args But obviously the real shell variables are long and ...
1
vote
2answers
48 views

env command shows 3 times same path

When I run env it shows 3 times /usr/bin under PATH. Same for every path under PATH title. For example - my scala bin directory shows 3 times. However, in my .bash_profile, it is written just one ...
6
votes
1answer
115 views

Is there any guarantee that /usr/bin/env will exist?

Often I will see scripts begin with a shebang line that uses #!/usr/bin/env interpreter_name for whatever interpreter, with the rationale that different systems might have the interpreter that they ...
2
votes
3answers
884 views

HowTo Chroot to BSD

I recently tried FreeBSD [9.2]. I installed it but as i found out it doesn't install any bootloader by default. So now i want to find out HOW it is possible to chroot to the installed BSD via a ...
7
votes
2answers
883 views

what is `env <command>` doing?

What is the command env ls -al doing? I had a Linux test and there was question: "How to run command directly, but not its alias?" I knew that there exists solution like prefixing command with some ...
5
votes
3answers
557 views

How to start a script with clean environment?

I tried the following but it doesn't seem to work: $ cat script.sh #!/bin/env -i /bin/sh /bin/env $ script.sh /bin/env: invalid option -- ' ' Try `/bin/env --help' for more information.
7
votes
3answers
532 views

Distributing a script: Should I use /bin/gawk or /usr/bin/gawk for shebang?

Is gawk in /bin or /usr/bin usually? I would go with #!/usr/bin/env gawk but then I can't use arguments. Right now I'm using #!/bin/gawk -f. The script is very long and contains a lot of single ...
3
votes
2answers
444 views

Why can't pgrep find scripts started via env?

For example: $ cat foo.sh #!/usr/bin/env bash while true; do sleep 1 ; done $ ./foo.sh & $ pgrep foo.sh $ Contrast with: $ cat bar.sh #!/bin/bash while true; do sleep 1 ; done $ ./bar.sh & ...
2
votes
2answers
3k views

/usr/bin/env: zsh -: No such file or directory

I get the error /usr/bin/env: zsh -: No such file or directory ...when I run an executable zsh script that starts with the following shebang line: #!/usr/bin/env zsh - Also, FWIW, replacing - ...
2
votes
1answer
701 views

How to get functions propagated to subshell?

Solaris / sh I have a few functions defined in a file which gets loaded via . ./some_file.sh When I start a subshell with sh All my function definitions are lost but when I do env I do ...
15
votes
1answer
2k views

Shebang line with `#!/usr/bin/env command --argument` fails on Linux

I've got a simple script: #!/usr/bin/env ruby --verbose # script.rb puts "hi" On my OSX box, it runs fine: osx% ./script.rb hi However, on my linux box, it throws an error linux% ./script.rb ...
6
votes
2answers
1k views

How do you specify alternative script interpreters (shebangs)?

In an executable file, you specify the environment using a shebang: #!/usr/bin/env ruby # ruby code here But what if you want to specify multiple possible environments? For example, if you have ...
85
votes
6answers
18k views

Why is it better to use “#!/usr/bin/env NAME” instead of “#!/path/to/NAME” as my shebang?

I notice that some scripts which I have acquired from others have the shebang #!/path/to/NAME while others (using the same tool, NAME) have the shebang #!/usr/bin/env NAME. Both seem to work ...
1
vote
4answers
864 views

chmod - change permissions on a file

I have a Python virtualenv, and the Python executable is located in the /bin directory. In this virtualenv I'll have to execute some unsafe code, that can damage my system. I tried to chmod a-r on the ...
8
votes
3answers
3k views

The way to use `/usr/bin/env sed -f ` in shebang?

Typing /usr/bin/env sed -f in terminal works. But if use it as a shebang, #!/usr/bin/env sed -f s/a/b/ The script will be fail to execute: /usr/bin/env: sed -f: No such file or directory I ...