I try to do it like:
(shell/sh "echo" '"$?")
However, it returns
{:exit 0, :out "$?\n", :err ""}
So how can I give $? as an argument but string to "echo" with clojure.java.shell?
When you execute a command in Bash, the return value of the program will be bound to $?. It means that when you execute echo "$?" in bash it will replace $? with the last return value and only then call the echo command. It is internal to bash (and bash-like shells) and not available in other programming language such as Java or Clojure.
Clojure's clojure.java.shell/sh basically calls Runtime.getRuntime().exec(...). The return value will be under the :exit key of the returned map.
An example to a successful sh call:
(clojure.java.shell/sh "ls" "target")
=>
{:exit 0, :out "classes\nrepl-port\nstale\n", :err ""}
An unsuccessfull call:
(clojure.java.shell/sh "ls" "nothing")
=>
{:exit 2, :out "", :err "ls: cannot access 'nothing': No such file or directory\n"}
IMHO it's not possible to get what you want with shell/sh.
When you run echo $? in the shell, the shell rewrites it into echo 0 (assuming that the last command is successful).
when you run shell/sh, it just invokes the **Runtime.exec(["echo" '"$?"]) in background. $? is passed to echo and echo has no idea what $ means.
Related
OS: Linux raspberrypi 4.19.58-v7l+ #1245 SMP Fri Jul 12 17:31:45 BST 2019 armv7l GNU/Linux
Board: Raspberry Pi 4
I have a script:
#!/bin/bash
line=$(head -n 1 /var/www/html/configuration.txt)
file=/var/www/html/4panel/url_response.txt
if [ -f "$file" ]; then
wget_output=$(wget -q -i "$line" -O $file --timeout=2)
echo "$?"
else
echo > $file
chown pi:pi $file
fi
which I call from a C++ program using:
int val_system = 0;
val_system = system("/var/www/html/4panel/get_page.sh");
std::cout<<"System return value: "<<val_system<<std::endl;
If there is something wrong with the script, echo "$?" will output the return value of wget, but val_system will always be 0.
Does system() returns the value of echo "$?" ? In which case 0 is correct. And if that is the case how can I put the return value of wget in val_system ?
I have taken a situation in which echo "$?" always returns 8, basically I've entered an incorrect URL and:
I have tried deleting echo "$?" but val_system still returned 0;
With echo "$?" deleted I have changed the wget line to wget -q -i "$line" -O $file --timeout=2 and val_system now returns 2048.
None of my attempts bared any fruit and I have come here to seek guidance. How can I make val_system / system() return what echo "$?" returns ?
How can I get the return value of wget from the script into an int variable that's inside the C++ program that calls the script ?
The integer value system() returned contains extra information about executed command's status along with its exit code, see system() and Status Information. You need to extract exit code using WEXITSTATUS macro, like:
std::cout << "System return value: " << WEXITSTATUS(val_system) << std::endl;
If you want to echo the status and return it, you will need to save the value of $? to a variable, and exit with it explicitly.
wget_output=$(wget -q -i "$line" -O $file --timeout=2)
status=$?
...
echo $status
...
exit $status
If you don't need to execute echo or any other command between the call to wget and the end of the script, you can rely on the script exiting with the last status (i.e the one corresponding to the call to `wget) implicitly.
i need to convert os.system() to subprocess.call()
I have 2 complex commands executing inside os.system as (cmd1 +"&&"+cmd2), I need to convert it to subprocess.call() with shell=False(for security reasons)
example of my code :-
cmd1 ="echo paras"
cmd2 ="rm -rf paras1.txt"
os.system as (cmd1 +"&&"+cmd2)
I Tried:-
subprocess.call([cmd3,"&&",cmd4],shell=False)
subprocess.call(shlex.split(cmd3+ "&&" +cmd4),shell=False)
but failed in both cases, i need to know how can i run 2 commands inside subprocess.call() separated by "&&" with shell=False.
You need to execute the commands within a shell (for example bash):
import subprocess
shell = '/bin/bash' # you may need to adjust the path!
cmds = ['echo "foo"', '&&', 'echo "bar"']
cmd = [shell, '-c', ' '.join(cmds)]
print cmd
print subprocess.call(cmd, shell=False)
Output:
['/bin/bash', '-c', 'echo "foo" && echo "bar"']
foo
bar
0
I have a function read_command defined as:
function read_command {
local __newline __lines __input __newstr __tmp i;
exec 3< "$*";
__newline=$'\n';
__lines=();
while IFS= read <&3 -r __line && [ "$__line" != '####' ]; do
echo "$__line";
__lines+=("$__line");
done
while IFS= read <&3 -r __line && [ "$__line" != '####' ]; do
read -e -p "${__line#*:}$PS2" __input;
local ${__line%%:*}="$__input";
done
__command="";
for i in "${__lines[#]}"; do
__tmp=$(echo "${i}");
__command="${__command} ${__newline} ${__tmp}";
done
echo -e "$__command";
}
In the current directory there is a file named "test", with the following
content:
greet ${a:-"Bob"}
greet ${b:-"Jim"}
####
a: name of friend a
b: name of friend b
####
In the terminal, the command executed is
read_command test
With no input, I am expecting the output of the last statement to be:
greet Bob
greet Jim
But what I get is:
greet ${a:-"Bob"}
greet ${b:-"Jim"}
What is wrong here?
Edit: As suggested by David, adding eval works in some cases except the following one.
j=1;i="export DISPLAY=:0 && Xephyr :${j}&";k=$(eval echo "$i");
echo $k
export DISPLAY=:0
I am expecting k to be "export DISPLAY=:0 && Xephyr :1&", what's wrong here?
Edit: I tried with the following
k=$(eval "echo \"$i\"")
This is the link to the script I am working on.
https://gist.github.com/QiangF/565102ba3b6123942b9bf6b897c05f87
During the first while loop, in echo "$__line", you have __line='greet ${a:-"Bob"}'. When you try to print that, Bash won't be expanding ${a:-"Bob"} into Bob. (Even if you remove the quotes around $__line this won't happen.) To get that effect, you need to add eval, as in, e.g., eval echo "$__line". Unfortunately eval comes with its can of worms, you have to start worrying about interactions between quoting levels and such.
I'm trying to write a program that will allow easier management of Arduino projects. So I wrote bash script that creates all the necessary folders and files for me and when I execute it I runs like champ. Because I want to change directory in the working terminal inside the script I run script like this
. ./initialize.sh
This is also working great, but because I am writing C++ program, sourcing this script from program is giving me headache.
So inside a program I run this script like this:
system(". /usr/lib/avrduino/script/initialize.sh");
and then when I run the program I get this error:
sh: 25: /usr/lib/avrduino/script/initialize.sh: Syntax error: "(" unexpected (expecting "}")
Running the script from the program like this:
system("/usr/lib/avrduino/script/initialize.sh");
works without error but it runs in subshell.
Syntax error points to this line in script
options=("uno" "mega" "mega2560" "atmega8" "atmega168" "atmega328" "pro" "pro5v" "pro328" "pro5v328")
How come that when I run this script outside of the program it's working like champ, but run this script from program and you have a problem ?
EDIT:
Script code
#!/bin/bash
BLACK='\033[0;30m'
RED='\033[0;31m'
GREEN='\033[0;32m'
BROWN='\033[0;33m'
BLUE='\033[0;34m'
PURPLE='\033[0;35m'
CYAN='\033[0;36m'
LGRAY='\033[0;37m'
DGRAY='\033[1;30m'
LRED='\033[1;31m'
LGREEN='\033[1;32m'
YELLOW='\033[1;33m'
LBLUE='\033[1;34m'
LPURPLE='\033[1;35m'
LCYAN='\033[1;36m'
WHITE='\033[1;37m'
NC='\033[0m'
makefile()
{
BOARD="default"
PS3='Chose your board: '
options=("uno" "mega" "mega2560" "atmega8" "atmega168" "atmega328" "pro" "pro5v" "pro328" "pro5v328")
select opt in "${options[#]}"
do case $opt in
"uno") BOARD="uno"
cp -r /usr/lib/avrduino/data/boards_info/uno/board-info.h .
MCU="atmega328P"
F_CPU="16000000UL"
;;
"mega") BOARD="mega"
cp -r /usr/lib/avrduino/data/boards_info/mega/board-info.h .
F_CPU="16000000UL"
;;
"mega2560") BOARD="mega2560"
cp -r /usr/lib/avrduino/data/boards_info/mega2560/board-info.h .
F_CPU="16000000UL"
;;
"atmega8") BOARD="atmega8"
cp -r /usr/lib/avrduino/data/boards_info/atmega8/board_-nfo.h .
MCU="atmega8"
F_CPU="16000000UL"
;;
"atmega168") BOARD="atmega168"
cp -r /usr/lib/avrduino/data/boards_info/atmega168/board-info.h .
MCU="atmega168"
F_CPU="16000000UL"
;;
"atmega328") BOARD="atmega328"
cp -r /usr/lib/avrduino/data/boards_info/atmega328/board-info.h .
MCU="atmega328P"
F_CPU="16000000UL"
;;
"pro") BOARD="pro"
cp -r /usr/lib/avrduino/data/boards_info/pro/board-info.h .
MCU="unknow"
F_CPU="16000000UL"
;;
"pro5v") BOARD="pro5v"
cp -r /usr/lib/avrduino/data/boards_info/pro5v/board-info.h .
MCU="unknown"
F_CPU="16000000UL"
;;
"pro328") BOARD="pro328"
cp -r /usr/lib/avrduino/data/boards_info/pro328/board-info.h .
MCU="atmega328P"
F_CPU="16000000UL"
;;
"pro5v328") BOARD= "pro5v328"
cp -r /usr/lib/avrduino/data/boards_info/pro5v328/board-info.h .
MCU="atmega328P"
F_CPU="16000000UL"
;;
*)
echo "Error : Input is not valid"
echo "Exiting..."
return 1
;;
esac
break
done
[ -e Makefile ] && rm Makefile
read -p "Do you want to configure your Makefile settings [Y/n]: " CONFIGURE
if { [ "$CONFIGURE" == "Y" ] || [ "$CONFIGURE" == "y" ]; }; then
read -p "Enter your MCU: " MCU
read -p "Enter F_CPU: " F_CPU
fi
read -p "Enter ARDUINO_PORT: " ARDUINO_PORT
echo "ARDUINO_DIR = /usr/share/arduino">>Makefile
echo "BOARD_TAG = $BOARD">>Makefile
echo "ARDUINO_PORT = $ARDUINO_PORT">>Makefile
echo "NO_CORE = 1">>Makefile
echo "AVRDUDE_ARD_PROGRAMMER = arduino">>Makefile
echo "HEX_MAXIMUM_SIZE = 30720">>Makefile
echo "AVRDUDE_ARD_BAUDRATE = 115200">>Makefile
echo "#ISP_LOW_FUSE = 0xFF">>Makefile
echo "#ISP_HIGH_FUSE = 0xDA">>Makefile
echo "#ISP_EXT_FUSE = 0x05">>Makefile
echo "#ISP_LOCK_FUSE_PRE = 0x3F">>Makefile
echo "#ISP_LOCK_FUSE_POST = 0x0F">>Makefile
echo "MCU = $MCU">>Makefile
echo "F_CPU = $F_CPU">>Makefile
echo "VARIANT = standard">>Makefile
echo "ARDUINO_LIBS =">>Makefile
echo "include /usr/share/arduino/Arduino.mk">>Makefile
echo "$BOARD|$MCU|" >> .avrduino.txt
clear
echo -e "${LGREEN}Makefile settings${NC}"
echo -e "${LBLUE}ARDUINO_DIR = ${LRED}/usr/share/arduino ${NC}"
echo -e "${LBLUE}BOARD_TAG = ${LRED}$BOARD${NC}"
echo -e "${LBLUE}ARDUINO_PORT = ${LRED}$ARDUINO_PORT${NC}"
echo -e "${LBLUE}NO_CORE = ${LRED}1${NC}"
echo -e "${LBLUE}AVRDUDE_ARD_PROGRAMMER = ${LRED}arduino${NC}"
echo -e "${LBLUE}HEX_MAXIMUM_SIZE = ${LRED}30720${NC}"
echo -e "${LBLUE}AVRDUDE_ARD_BAUDRATE = ${LRED}115200${NC}"
echo -e "${DGRAY}#ISP_LOW_FUSE = ${RED}0xFF${NC}"
echo -e "${DGRAY}#ISP_HIGH_FUSE = ${RED}0xDA${NC}"
echo -e "${DGRAY}#ISP_EXT_FUSE = ${RED}0x05${NC}"
echo -e "${DGRAY}#ISP_LOCK_FUSE_PRE = ${RED}0x3F${NC}"
echo -e "${DGRAY}#ISP_LOCK_FUSE_POST = ${RED}0x0F${NC}"
echo -e "${LBLUE}MCU = ${LRED}$MCU${NC}"
echo -e "${LBLUE}F_CPU = ${LRED}$F_CPU${NC}"
echo -e "${LBLUE}VARIANT = ${LRED}standard${NC}"
echo -e "${LBLUE}ARDUINO_LIBS =${NC}"
}
initializeProject()
{
read -p "Project name: " PROJECT_NAME
if [ ! -e PROJECT_NAME ]; then
mkdir $PROJECT_NAME
cd $PROJECT_NAME
makefile #Call function that makes makefile
cp -r /usr/lib/avrduino/data/include/ .
echo -e "${LGREEN}Project created successfully ${NC}"
else
echo "AVRduino: Project with name [ $PROJECT_NAME ] already exists. "
echo "AVRduino: Stop project wizard and exit."
fi
}
clear
initializeProject
. doesn't execute the script as a process, it only loads it into your current shell process.
In that context, your "shebang" line, #!/bin/bash, is just a comment.
(You can put #! doodle poodle noodle there and it will run just as well.)
When you use system, it executes in /bin/sh, and thus your bash script has syntax errors.
One way to execute scripts is to make them executable:
chmod +x /usr/lib/avrduino/script/initialize.sh
and then you can just pass it directly to system:
system("/usr/lib/avrduino/script/initialize.sh");
Or, you could explictly execute it in bash:
system("/bin/bash /usr/lib/avrduino/script/initialize.sh");
OK, here's a way one might solve your "changing directory" problem:
Rewrite initialize.sh so it takes the project name as an argument instead of asking for it interactively (that's how normal Unix tools work, so stick with it).
Then add the following to your .bashrc:
make_project()
{
/usr/lib/avrduino/script/initialize.sh "$1" && cd "$1"
}
Then you can say make_project foo and get transported to the directory "foo".
Most likely it is the misplaced shebang causing a default shell to be run - make sure the shebang is at the beginning of the first line
#!/bin/bash
# rest of script
If that does not work change your system call to
system("/bin/bash /usr/lib/avrduino/script/initialize.sh");
I have a problem with printing the stack trace (back-trace) of a demon which is created for C++ application. service is based on /etc/init.d/ init script based architecture and I have seen several services followed the same to deliver applications as services in Linux. in this case when stopping my service by service name stop stack trace of the program is printing on the console. This backtrace contains the uncleaned memory map of the program.
I just need to avoid printing this on the terminal and save it into a separate file till I fix the memory issues of the program.
EDITED:
Can this do by adding more commands to the init script ?
Is there any compilation option to avoid printing the program
stack-trace after stopping the program ?
Can a block of c/c++ source code use to handle this ?
Below is my /etc/init.d/init script.
# Source function library.
. /etc/rc.d/init.d/functions
cscored=${CSCORED-/opt/application-name/bin/cscore &}
prog=cscored
pidfile=${PIDFILE-/var/run/cscored/cscored.pid}
lockfile=${LOCKFILE-/var/lock/subsys/cscored}
RETVAL=0
STOP_TIMEOUT=${STOP_TIMEOUT-10}
start() {
echo -n $"Starting $prog: "
daemon $cscored
RETVAL=$?
echo
[ $RETVAL = 0 ] && touch ${lockfile}
return $RETVAL
}
stop() {
echo -n $"Stopping $prog: "
killproc $cscored
RETVAL=$?
echo
[ $RETVAL = 0 ] && rm -f ${lockfile} ${pidfile}
}
reload() {
echo -n $"Reloading $prog: "
if ! $cscored -t >&/dev/null; then
RETVAL=6
echo $"not reloading due to configuration syntax error"
failure $"not reloading $cscored due to configuration syntax error"
else
# Force LSB behaviour from killproc
LSB=1 killproc -p ${pidfile} $cscored -HUP
RETVAL=$?
if [ $RETVAL -eq 7 ]; then
failure $"cscored shutdown"
fi
fi
echo
}
# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
status)
status $cscored
RETVAL=$?
;;
restart)
stop
start
;;
condrestart|try-restart)
if status $cscored >&/dev/null; then
stop
start
fi
;;
force-reload|reload)
reload
;;
*)
echo $"Usage: $prog {start|stop|restart|condrestart|try-restart|force-reload|reload|status|fullstatus|graceful|help|configtest}"
RETVAL=2
esac
exit $RETVAL
You can redirect the output of the console to another file either using a pipe or dup().