exit not terminating the script

Clash Royale CLAN TAG#URR8PPP

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1
down vote

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exit doesn't terminate the script when error is called..

output

Error: Could not resolve localhost
after exit

script

#!/bin/sh

resolve_ip ()
 if [ -z "$1" ]; then
 host="localhost"
 ip=$(dig +short myip.opendns.com @resolver1.opendns.com)
 else
 host="$1"
 ip=$(dig +short $1)
 fi

 if [ -z "$ip" ]; then
 error "Could not resolve $host"
 fi

 echo "$ip"


error ()
 (>&2 echo "Error: $1")
 exit 1


master_host='google.com'

if [ "$(resolve_ip)" = "$(resolve_ip $master_host)" ]; then
 error "some error"
fi

echo "after exit"
exit

shell

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asked 38 mins ago

clarkk

48241122

add a comment | 

up vote
1
down vote

favorite

exit doesn't terminate the script when error is called..

output

Error: Could not resolve localhost
after exit

script

#!/bin/sh

resolve_ip ()
 if [ -z "$1" ]; then
 host="localhost"
 ip=$(dig +short myip.opendns.com @resolver1.opendns.com)
 else
 host="$1"
 ip=$(dig +short $1)
 fi

 if [ -z "$ip" ]; then
 error "Could not resolve $host"
 fi

 echo "$ip"


error ()
 (>&2 echo "Error: $1")
 exit 1


master_host='google.com'

if [ "$(resolve_ip)" = "$(resolve_ip $master_host)" ]; then
 error "some error"
fi

echo "after exit"
exit

shell

share|improve this question

asked 38 mins ago

clarkk

48241122

add a comment | 

up vote
1
down vote

favorite

up vote
1
down vote

favorite

exit doesn't terminate the script when error is called..

output

Error: Could not resolve localhost
after exit

script

#!/bin/sh

resolve_ip ()
 if [ -z "$1" ]; then
 host="localhost"
 ip=$(dig +short myip.opendns.com @resolver1.opendns.com)
 else
 host="$1"
 ip=$(dig +short $1)
 fi

 if [ -z "$ip" ]; then
 error "Could not resolve $host"
 fi

 echo "$ip"


error ()
 (>&2 echo "Error: $1")
 exit 1


master_host='google.com'

if [ "$(resolve_ip)" = "$(resolve_ip $master_host)" ]; then
 error "some error"
fi

echo "after exit"
exit

shell

share|improve this question

asked 38 mins ago

clarkk

48241122

exit doesn't terminate the script when error is called..

output

Error: Could not resolve localhost
after exit

script

#!/bin/sh

resolve_ip ()
 if [ -z "$1" ]; then
 host="localhost"
 ip=$(dig +short myip.opendns.com @resolver1.opendns.com)
 else
 host="$1"
 ip=$(dig +short $1)
 fi

 if [ -z "$ip" ]; then
 error "Could not resolve $host"
 fi

 echo "$ip"


error ()
 (>&2 echo "Error: $1")
 exit 1


master_host='google.com'

if [ "$(resolve_ip)" = "$(resolve_ip $master_host)" ]; then
 error "some error"
fi

echo "after exit"
exit

shell

shell

share|improve this question

asked 38 mins ago

clarkk

48241122

share|improve this question

asked 38 mins ago

clarkk

48241122

share|improve this question

share|improve this question

asked 38 mins ago

clarkk

48241122

asked 38 mins ago

clarkk

48241122

asked 38 mins ago

clarkk

48241122

48241122

add a comment | 

add a comment | 

1 Answer
1

active

oldest

votes

up vote
4
down vote

exit exits the current shell process¹.

In $(resolve_ip), resolve_ip is running in a subshell process.

You can do:

 my_ip=$(resolve_ip) || exit
 master_ip=$(resolve_ip "$hostname") || exit
 if [ "$my_ip" = "$master_ip" ]; ...

For the main shell to exit (with the same exit code as the subshell) when the subshell exits with a non-zero exit status.

Also, as resolve_ip is run in a subshell environment, the $ip and $host variables will not survive after that subshell returns.

Also note that the (...) in (>&2 echo "Error: $1") also starts a subshell. Not really necessary here unless you want to cover for the case where stderr is a broken pipe and writing the error message would cause a SIGPIPE delivery to the main shell process as echo is builtin.

---

^{¹ Strictly speaking subshell environments don't have to be implemented with child processes, and some shells like ksh93 don't as an optimisation, but still exit there only exits the subshell, not the main shell. ksh93 however has a $ ...; form or command substitution that doesn't involve a subshell environment, so exit in that would exit the main shell.}

share|improve this answer

edited 29 mins ago

answered 34 mins ago

Stéphane Chazelas

289k54536875

add a comment | 

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
4
down vote

exit exits the current shell process¹.

In $(resolve_ip), resolve_ip is running in a subshell process.

You can do:

 my_ip=$(resolve_ip) || exit
 master_ip=$(resolve_ip "$hostname") || exit
 if [ "$my_ip" = "$master_ip" ]; ...

For the main shell to exit (with the same exit code as the subshell) when the subshell exits with a non-zero exit status.

Also, as resolve_ip is run in a subshell environment, the $ip and $host variables will not survive after that subshell returns.

Also note that the (...) in (>&2 echo "Error: $1") also starts a subshell. Not really necessary here unless you want to cover for the case where stderr is a broken pipe and writing the error message would cause a SIGPIPE delivery to the main shell process as echo is builtin.

---

^{¹ Strictly speaking subshell environments don't have to be implemented with child processes, and some shells like ksh93 don't as an optimisation, but still exit there only exits the subshell, not the main shell. ksh93 however has a $ ...; form or command substitution that doesn't involve a subshell environment, so exit in that would exit the main shell.}

share|improve this answer

edited 29 mins ago

answered 34 mins ago

Stéphane Chazelas

289k54536875

add a comment | 

up vote
4
down vote

exit exits the current shell process¹.

In $(resolve_ip), resolve_ip is running in a subshell process.

You can do:

 my_ip=$(resolve_ip) || exit
 master_ip=$(resolve_ip "$hostname") || exit
 if [ "$my_ip" = "$master_ip" ]; ...

For the main shell to exit (with the same exit code as the subshell) when the subshell exits with a non-zero exit status.

Also, as resolve_ip is run in a subshell environment, the $ip and $host variables will not survive after that subshell returns.

Also note that the (...) in (>&2 echo "Error: $1") also starts a subshell. Not really necessary here unless you want to cover for the case where stderr is a broken pipe and writing the error message would cause a SIGPIPE delivery to the main shell process as echo is builtin.

---

^{¹ Strictly speaking subshell environments don't have to be implemented with child processes, and some shells like ksh93 don't as an optimisation, but still exit there only exits the subshell, not the main shell. ksh93 however has a $ ...; form or command substitution that doesn't involve a subshell environment, so exit in that would exit the main shell.}

share|improve this answer

edited 29 mins ago

answered 34 mins ago

Stéphane Chazelas

289k54536875

add a comment | 

up vote
4
down vote

up vote
4
down vote

exit exits the current shell process¹.

In $(resolve_ip), resolve_ip is running in a subshell process.

You can do:

 my_ip=$(resolve_ip) || exit
 master_ip=$(resolve_ip "$hostname") || exit
 if [ "$my_ip" = "$master_ip" ]; ...

For the main shell to exit (with the same exit code as the subshell) when the subshell exits with a non-zero exit status.

Also, as resolve_ip is run in a subshell environment, the $ip and $host variables will not survive after that subshell returns.

Also note that the (...) in (>&2 echo "Error: $1") also starts a subshell. Not really necessary here unless you want to cover for the case where stderr is a broken pipe and writing the error message would cause a SIGPIPE delivery to the main shell process as echo is builtin.

---

^{¹ Strictly speaking subshell environments don't have to be implemented with child processes, and some shells like ksh93 don't as an optimisation, but still exit there only exits the subshell, not the main shell. ksh93 however has a $ ...; form or command substitution that doesn't involve a subshell environment, so exit in that would exit the main shell.}

share|improve this answer

edited 29 mins ago

answered 34 mins ago

Stéphane Chazelas

289k54536875

exit exits the current shell process¹.

In $(resolve_ip), resolve_ip is running in a subshell process.

You can do:

 my_ip=$(resolve_ip) || exit
 master_ip=$(resolve_ip "$hostname") || exit
 if [ "$my_ip" = "$master_ip" ]; ...

For the main shell to exit (with the same exit code as the subshell) when the subshell exits with a non-zero exit status.

Also, as resolve_ip is run in a subshell environment, the $ip and $host variables will not survive after that subshell returns.

Also note that the (...) in (>&2 echo "Error: $1") also starts a subshell. Not really necessary here unless you want to cover for the case where stderr is a broken pipe and writing the error message would cause a SIGPIPE delivery to the main shell process as echo is builtin.

---

^{¹ Strictly speaking subshell environments don't have to be implemented with child processes, and some shells like ksh93 don't as an optimisation, but still exit there only exits the subshell, not the main shell. ksh93 however has a $ ...; form or command substitution that doesn't involve a subshell environment, so exit in that would exit the main shell.}

share|improve this answer

edited 29 mins ago

answered 34 mins ago

Stéphane Chazelas

289k54536875

share|improve this answer

share|improve this answer

edited 29 mins ago

edited 29 mins ago

edited 29 mins ago

answered 34 mins ago

Stéphane Chazelas

289k54536875

answered 34 mins ago

Stéphane Chazelas

289k54536875

answered 34 mins ago

Stéphane Chazelas

289k54536875

289k54536875

add a comment | 

add a comment | 

 

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