08-06-2007
Very Strange Behavior for redirection
I have searched far and wide for an explanation for some odd behavior for output redirection and haven't come up with anything.
A co-worker was working on old scripts which have run for years and embedded in their code were output redirects which worked for the script during execution and then reset back to normal output after the script completed. He tested the same script on a Solaris 10 box and found that the redirection continued after the script finished. I think that the redirection being persistent is normal, (one expects items set in a shell script to remain after execution i.e. .profiles etc.) the return to normal output seems to be the oddity. I have tested on several different boxes featuring solaris 8 9 and 10, and I get the same results everytime, the redirection persists.
Redirecting stdout works and stdout is redirected properly to the file. However, when trying a command like 2>&1 1>filename, this has the effect of redirecting stdout, but not stderr. (In testing the stderr came back to the terminal, and only stdout stuff went to the file)
If you run the code below, and you seem to lose the standard output, stdout can be recaptured to the tty using exec 1>/dev/tty on the command line and things get back to normal.
When stderr is redirected instead however, all output goes to the file, and the result feels like the session has hung. There doesn't seem to be any interaction. Closing the terminal seems to be the only option
I am interested to know if anyone else can replicate this behavior on their environments, and if anyone can suggest some reasons for it.
OS = Solaris 8,9,10
Arch = SPARC (Fujitsu clone)
Thanks
####################################
## CODE LINES
####################################
#!/bin/ksh
echo "Begin Testing, output to TTY"
# uncomment the following line to test stdout redirection
exec 1> output.file
echo "This should be in the file"
# uncomment the following line to test stderror redirection
# exec 2> output.file
#uncomment the following line to test dual redirection
#exec 2>$1 1>output.file
# Create an Error that should go out to the file
cat asdfasdfasdf
############################################
## END CODE
############################################
###
TESTING PROTOCOL
## The command line is :
>. test.sh
Begin Testing, output to TTY
cat: cannot open asdfasdfasdf
## after the script completes, try to obtain some output to the terminal
> ls -al
No result
> exec 1>/dev/tty
Recapture the stdout to the terminal screen
> cat output.file
This should be in the file
total 12
-rw-r--r-- 1 cogcrn cogcrn 0 Aug 6 16:27 -
drwxr-xr-x 2 cogcrn cogcrn 512 Aug 6 16:27 .
drwxr-xr-x 25 cogcrn cogcrn 1536 Aug 6 16:09 ..
-rwxr-xr-x 1 cogcrn cogcrn 969 Jun 13 13:00 ldap_query.pl
-rw-r--r-- 1 cogcrn cogcrn 27 Aug 6 18:52 output.file
-rw-r--r-- 1 cogcrn cogcrn 0 Aug 6 16:26 TERM
-rw-r--r-- 1 cogcrn cogcrn 394 Aug 6 18:49 test.sh
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npm-run-script
NPM-RUN-SCRIPT(1) NPM-RUN-SCRIPT(1)
NAME
npm-run-script - Run arbitrary package scripts
SYNOPSIS
npm run-script <command> [--silent] [-- <args>...]
alias: npm run
DESCRIPTION
This runs an arbitrary command from a package's "scripts" object. If no "command" is provided, it will list the available scripts.
run[-script] is used by the test, start, restart, and stop commands, but can be called directly, as well. When the scripts in the package
are printed out, they're separated into lifecycle (test, start, restart) and directly-run scripts.
As of ` https://blog.npmjs.org/post/98131109725/npm-2-0-0, you can use custom arguments when executing scripts. The special option -- is
used by getopt https://goo.gl/KxMmtG to delimit the end of the options. npm will pass all the arguments after the -- directly to your
script:
npm run test -- --grep="pattern"
The arguments will only be passed to the script specified after npm run and not to any pre or post script.
The env script is a special built-in command that can be used to list environment variables that will be available to the script at run-
time. If an "env" command is defined in your package, it will take precedence over the built-in.
In addition to the shell's pre-existing PATH, npm run adds node_modules/.bin to the PATH provided to scripts. Any binaries provided by
locally-installed dependencies can be used without the node_modules/.bin prefix. For example, if there is a devDependency on tap in your
package, you should write:
"scripts": {"test": "tap test/*.js"}
instead of
"scripts": {"test": "node_modules/.bin/tap test/*.js"}
to run your tests.
The actual shell your script is run within is platform dependent. By default, on Unix-like systems it is the /bin/sh command, on Windows it
is the cmd.exe. The actual shell referred to by /bin/sh also depends on the system. As of `
https://github.com/npm/npm/releases/tag/v5.1.0 you can customize the shell with the script-shell configuration.
Scripts are run from the root of the module, regardless of what your current working directory is when you call npm run. If you want your
script to use different behavior based on what subdirectory you're in, you can use the INIT_CWD environment variable, which holds the full
path you were in when you ran npm run.
npm run sets the NODE environment variable to the node executable with which npm is executed. Also, if the --scripts-prepend-node-path is
passed, the directory within which node resides is added to the PATH. If --scripts-prepend-node-path=auto is passed (which has been the
default in npm v3), this is only performed when that node executable is not found in the PATH.
If you try to run a script without having a node_modules directory and it fails, you will be given a warning to run npm install, just in
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You can use the --silent flag to prevent showing npm ERR! output on error.
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SEE ALSO
o npm help 7 scripts
o npm help test
o npm help start
o npm help restart
o npm help stop
o npm help 7 config
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