I write this code in my rails project.It's to execute a shell script ,But my shell script can catch #directdown only.
rails script
#cmd = "/downafile.sh #{#directdown} #{#file.id} #{#filename}"
`#{#cmd}`
shell script
echo $1 >> /tmp/ceshi.tmp
echo $2 >> /tmp/ceshi.tmp
echo $3 >> /tmp/ceshi.tmp
Thanks.
`` and system command works in similar manner.
But system method will return true on success.
Try with this:
#cmd = "/downafile.sh '#{#directdown}' '#{#file.id}' '#{#filename}'"
`#{#cmd}`
Try using puts #cmd to see the command generated and see whether the command is what you intended. If it is try executing it from the terminal to test whether your shell script works. I think the parameters #file.id and #filename value may be nil so on interpolation it will be replaced by "". puts their values also to check.
I don't know what is the meaning of `` in Ruby, but I think you can use the system function to invoke an external program. Something like,
#cmd = "/downafile.sh #{#directdown} #{#file.id} #{#filename}"
system(#cmd)
Hope it helps.
Related
I am trying to write a dockerfile in which I add a few java-options to a script called envvars.
To achieve that I want to append a few text-lines to said file like so:
RUN echo "JAVA_OPTS=$JAVA_OPTS -Djavax.net.ssl.trustStore=${CERT_DIR}/${HOSTNAME}_truststore.jks" >> ${BIN_DIR}/envvars
RUN echo "JAVA_OPTS=$JAVA_OPTS -Djavax.net.ssl.trustStorePassword=${PWD_TRUSTSTORE}" >> ${BIN_DIR}/envvars
RUN echo "export JAVA_OPTS" >> ${BIN_DIR}/envvars
The issue here is, that I want the misc. placeholders ${varname} (those with curly braces) to be replaced during execution of the docker build command while the substring '$JAVA_OPTS' (i.e. those without braces) should be echoed and thus added to the envvars file verbatim, i.e. in the end the result in the /usr/local/apache2/bin/envvars file should read:
...
JAVA_OPTS=$JAVA_OPTS -Djavax.net.ssl.trustStore=/usr/local/apache2/cert/myserver_truststore.jks
JAVA_OPTS=$JAVA_OPTS -Djavax.net.ssl.trustStorePassword=my_secret
export JAVA_OPTS
How can one escape a $-sign from variable substitution in dockerfiles?
I found hints to use \$ or $$ but neither worked for me.
In case that matters (which I hope/expect not to): I am building the image using "Docker Desktop" on Windows 10 but I would expect the dockerfile to be agnostic of that.
first you need to add this # escape=` to your Dockerfile since \ is an escape charachter in the Dockerfile . then you can use \$ to escape the dollar sign in the RUN section
Example:
# escape=`
RUN echo "JAVA_OPTS=\$JAVA_OPTS -Djavax.net.ssl.trustStore=${CERT_DIR}/${HOSTNAME}_truststore.jks" >> ${BIN_DIR}/envvars
that will be JAVA_OPTS=$JAVA_OPTS in your env file
I have a Lua script and in there I open a minicom session which executes a script (with the -S" parameter).
local myFile = assert(io.popen('minicom -S myScript.sh ' myDevice ' -C myLogFile.log'))
local myFileOutput = myFile:read('*all')
myFile:close()
This works really fine.
But I would like to get the same output as if I execute the minicom command itself:
minicom -S myScript.sh ' myDevice ' -C myLogFile.log
Right now I don't get any output at all (I know that that's somehow obvious).
I would that the output should also occur at (at least nearly) the same time as with the minicom command itself. Not one big chuck of data at the end.
Does anyone know how to achieve that?
If I understand you correctly, you need something like
local myFile = assert(io.popen('minicom ...'))
for line in myFile:lines('l') do
print(line)
end
myFile:close()
I was following this simple tutorial to try out a simple lua script
http://www.redisgreen.net/blog/2013/03/18/intro-to-lua-for-redis-programmers/
I created a simple hello.lua file with these lines
local msg = "Hello, world!"
return msg
And i tried running simple command
EVAL "$(cat /Users/rsingh/Downloads/hello.lua)" 0
And i am getting this error
(error) ERR Error compiling script (new function): user_script:1: unexpected symbol near '$'
I can't find what is wrong here and i haven't been able to find someone who has come across this.
Any help would be deeply appreciated.
Your problem comes from the fact you are executing this command from an interactive Redis session:
$ redis-cli
127.0.0.1:6379> EVAL "$(cat /path/to/hello.lua)" 0
(error) ERR Error compiling script (new function): user_script:1: unexpected symbol near '$'
Within such a session you cannot use common command-line tools like cat et al. (here cat is used as a convenient way to get the content of your script in-place). In other words: you send "$(cat /path/to/hello.lua)" as a plain string to Redis, which is not Lua code (of course), and Redis complains.
To execute this sample you must stay in the shell:
$ redis-cli EVAL "$(cat /path/to/hello.lua)" 0
"Hello, world!"
If you are coming from windows and trying to run a lua script you should use this format:
redis-cli --eval script.lua
Run this from the folder where your script is located and it will load a multi line file and execute it.
On the off chance that anyone's come to this from Windows instead, I found I had to do a lot of juggling to achieve the same effect. I had to do this:
echo “local msg = 'Hello, world!'; return msg” > hello.lua
for /F "delims=" %i in ('type hello.lua') do #set cmd=%i
redis-cli eval "%cmd%" 0
.. if you want it saved as a file, although you'll have to have all the content on one line. If you don’t just roll the content into a set command
set cmd=“local msg = 'Hello, world!'; return msg”
redis-cli eval "%cmd%" 0
I have written a shell script which executing some of the mysql commands.
I want to run that shell script from rails side. And want to get result back of commands to rails from shell script.
How may i handle it?
EDIT:
script.sh
mysql -u root -pmysql << eof
SELECT TABLE_NAME AS "Table Name", table_rows AS "Quant of Rows", ROUND((data_length + index_length)/1024/1024,2) AS "Total Size Mb" FROM information_schema.TABLES WHERE information_schema.TABLES.table_schema='database_name';
eof
This is my script. How may i return SELECT query result to rails ?
You can do something like this, it will block until the script is finished and any output that it sent to standard out will be contained in the output variable.
output = `/my/script.sh`
puts output
Use backticks ` `
`/path/to/script` #backticks
Edit
To get the output of a mysql statement, use the -e flag
Eg. mysql -e "SELECT * from information_schema"
I'm trying to set up a shell script that will start a screen session (or rejoin an existing one) only if it is invoked from an interactive shell. The solution I have seen is to check if $- contains the letter "i":
#!/bin/sh -e
echo "Testing interactivity..."
echo 'Current value of $- = '"$-"
if [ `echo \$- | grep -qs i` ]; then
echo interactive;
else
echo noninteractive;
fi
However, this fails, because the script is run by a new noninteractive shell, invoked as a result of the #!/bin/sh at the top. If I source the script instead of running it, it works as desired, but that's an ugly hack. I'd rather have it work when I run it.
So how can I test for interactivity within a script?
Give this a try and see if it does what you're looking for:
#!/bin/sh
if [ $_ != $0 ]
then
echo interactive;
else
echo noninteractive;
fi
The underscore ($_) expands to the absolute pathname used to invoke the script. The zero ($0) expands to the name of the script. If they're different then the script was invoked from an interactive shell. In Bash, subsequent expansion of $_ gives the expanded argument to the previous command (it might be a good idea to save the value of $_ in another variable in order to preserve it).
From man bash:
0 Expands to the name of the shell or shell script. This is set
at shell initialization. If bash is invoked with a file of com‐
mands, $0 is set to the name of that file. If bash is started
with the -c option, then $0 is set to the first argument after
the string to be executed, if one is present. Otherwise, it is
set to the file name used to invoke bash, as given by argument
zero.
_ At shell startup, set to the absolute pathname used to invoke
the shell or shell script being executed as passed in the envi‐
ronment or argument list. Subsequently, expands to the last
argument to the previous command, after expansion. Also set to
the full pathname used to invoke each command executed and
placed in the environment exported to that command. When check‐
ing mail, this parameter holds the name of the mail file cur‐
rently being checked.
$_ may not work in every POSIX compatible sh, although it probably works in must.
$PS1 will only be set if the shell is interactive. So this should work:
if [ -z "$PS1" ]; then
echo noninteractive
else
echo interactive
fi
try tty
if tty 2>&1 |grep not ; then echo "Not a tty"; else echo "a tty"; fi
man tty :
The tty utility writes the name of the terminal attached to standard
input to standard output. The name that is written is the string
returned by ttyname(3). If the standard input is not a terminal, the
message ``not a tty'' is written.
You could try using something like...
if [[ -t 0 ]]
then
echo "Interactive...say something!"
read line
echo $line
else
echo "Not Interactive"
fi
The "-t" switch in the test field checks if the file descriptor given matches a terminal (you could also do this to stop the program if the output was going to be printed to a terminal, for example). Here it checks if the standard in of the program matches a terminal.
Simple answer: don't run those commands inside ` ` or [ ].
There is no need for either of those constructs here.
Obviously I can't be sure what you expected
[ `echo \$- | grep -qs i` ]
to be testing, but I don't think it's testing what you think it's testing.
That code will do the following:
Run echo \$- | grep -qs i inside a subshell (due to the ` `).
Capture the subshell's standard output.
Replace the original ` ` expression with a string containing that output.
Pass that string as an argument to the [ command or built-in (depending on your shell).
Produce a successful return code from [ only if that string was nonempty (assuming the string didn't look like an option to [).
Some possible problems:
The -qs options to grep should cause it to produce no output, so I'd expect [ to be testing an empty string regardless of what $- looks like.
It's also possible that the backslash is escaping the dollar sign and causing a literal 'dollar minus' (rather than the contents of a variable) to be sent to grep.
On the other hand, if you removed the [ and backticks and instead said
if echo "$-" | grep -qs i ; then
then:
your current shell would expand "$-" with the value you want to test,
echo ... | would send that to grep on its standard input,
grep would return a successful return code when that input contained the letter i,
grep would print no output, due to the -qs flags, and
the if statement would use grep's return code to decide which branch to take.
Also:
no backticks would replace any commands with the output produced when they were run, and
no [ command would try to replace the return code of grep with some return code that it had tried to reconstruct by itself from the output produced by grep.
For more on how to use the if command, see this section of the excellent BashGuide.
If you want to test the value of $- without forking an external process (e.g. grep) then you can use the following technique:
if [ "${-%i*}" != "$-" ]
then
echo Interactive shell
else
echo Not an interactive shell
fi
This deletes any match for i* from the value of $- then checks to see if this made any difference.
(The ${parameter/from/to} construct (e.g. [ "${-//[!i]/}" = "i" ] is true iff interactive) can be used in Bash scripts but is not present in Dash, which is /bin/sh on Debian and Ubuntu systems.)