Exit Shell Script Based on Process Exit Code

Question

I have a shell script that executes a number of commands  How do I make the shell script exit if any of the commands exit with a non-zero exit code

User · Answer

In Bash this is easy  Just tie them together with  amp  amp   command1  amp  amp  command2  amp  amp  command3  You can also use the nested if construct  if command1    then        if command2            then                do something            else                exit        fi    else        exit fi

User · Answer

If you just call exit in Bash without any parameters  it will return the exit code of the last command  Combined with OR  Bash should only invoke exit  if the previous command fails  But I haven t tested this   command1    exit  command2    exit   Bash will also store the exit code of the last command in the variable

User · Answer

For Bash    This will trap any errors or commands with non-zero exit status   by calling function catch errors   trap catch errors ERR           the rest of the script goes here    function catch errors          Do whatever on errors              echo  quot script aborted  because of errors quot      exit 0

User · Answer

------------------------------------------------------------------------------   purpose  to run a command  log cmd output  exit on error   usage    set -e  do run cmd or exit  quot  cmd quot    set  e  ------------------------------------------------------------------------------ do run cmd or exit        cmd  quot    quot         do log  quot DEBUG running cmd or exit    quot  cmd  quot  quot      msg    cmd 2 gt  amp 1      export exit code           If occurred during the execution  exit with error     error msg  quot Failed to run the command            quot  cmd  quot  with the output            quot  msg  quot      quot       if    exit code -ne 0     then         do log  quot ERROR  msg quot          do log  quot FATAL  msg quot          do exit  quot  exit code quot   quot  error msg quot      else           If no errors occurred  just log the message         do log  quot DEBUG   cmdoutput     quot  msg  quot  quot      fi

User · Answer

After each command  the exit code can be found in the    variable so you would have something like   ls -al file ext rc     if     rc    0     then exit  rc  fi   You need to be careful of piped commands since the    only gives you the return code of the last element in the pipe so  in the code   ls -al file ext   sed  s   xx       will not return an error code if the file doesn t exist  since the sed part of the pipeline actually works  returning 0    The bash shell actually provides an array which can assist in that case  that being PIPESTATUS  This array has one element for each of the pipeline components  that you can access individually like   PIPESTATUS 0     pax gt  false   true   echo   PIPESTATUS 0   1   Note that this is getting you the result of the false command  not the entire pipeline  You can also get the entire list to process as you see fit   pax gt  false   true   false  echo   PIPESTATUS     1 0 1   If you wanted to get the largest error code from a pipeline  you could use something like   true   true   false   true   false rcs   PIPESTATUS      rc 0  for i in   rcs   do rc     i  gt   rc    i    rc    done echo  rc   This goes through each of the PIPESTATUS elements in turn  storing it in rc if it was greater than the previous rc value

User · Answer

In Bash this is easy  Just tie them together with  amp  amp   command1  amp  amp  command2  amp  amp  command3  You can also use the nested if construct  if command1    then        if command2            then                do something            else                exit        fi    else        exit fi

User · Answer

If you want to work with     you ll need to check it after each command  since    is updated after each command exits   This means that if you execute a pipeline  you ll only get the exit code of the last process in the pipeline  Another approach is to do this  set -e set -o pipefail  If you put this at the top of the shell script  it looks like Bash will take care of this for you   As a previous poster noted   quot set -e quot  will cause Bash to exit with an error on any simple command    quot set -o pipefail quot  will cause Bash to exit with an error on any command in a pipeline as well  See here or here for a little more discussion on this problem   Here is the Bash manual section on the set builtin

User · Answer

set -e  is probably the easiest way to do this  Just put that before any commands in your program

User · Answer

For Bash    This will trap any errors or commands with non-zero exit status   by calling function catch errors   trap catch errors ERR           the rest of the script goes here    function catch errors          Do whatever on errors              echo  quot script aborted  because of errors quot      exit 0

User · Answer

For Bash    This will trap any errors or commands with non-zero exit status   by calling function catch errors   trap catch errors ERR           the rest of the script goes here    function catch errors          Do whatever on errors              echo  quot script aborted  because of errors quot      exit 0

User · Answer

For Bash    This will trap any errors or commands with non-zero exit status   by calling function catch errors   trap catch errors ERR           the rest of the script goes here    function catch errors          Do whatever on errors              echo  quot script aborted  because of errors quot      exit 0

User · Answer

In Bash this is easy  Just tie them together with  amp  amp   command1  amp  amp  command2  amp  amp  command3  You can also use the nested if construct  if command1    then        if command2            then                do something            else                exit        fi    else        exit fi

User · Answer

If you want to work with     you ll need to check it after each command  since    is updated after each command exits   This means that if you execute a pipeline  you ll only get the exit code of the last process in the pipeline  Another approach is to do this  set -e set -o pipefail  If you put this at the top of the shell script  it looks like Bash will take care of this for you   As a previous poster noted   quot set -e quot  will cause Bash to exit with an error on any simple command    quot set -o pipefail quot  will cause Bash to exit with an error on any command in a pipeline as well  See here or here for a little more discussion on this problem   Here is the Bash manual section on the set builtin

User · Answer

If you just call exit in Bash without any parameters  it will return the exit code of the last command  Combined with OR  Bash should only invoke exit  if the previous command fails  But I haven t tested this   command1    exit  command2    exit   Bash will also store the exit code of the last command in the variable

User · Answer

If you just call exit in Bash without any parameters  it will return the exit code of the last command  Combined with OR  Bash should only invoke exit  if the previous command fails  But I haven t tested this   command1    exit  command2    exit   Bash will also store the exit code of the last command in the variable

User · Answer

http   cfaj freeshell org shell cus-faq-2 html 11  How do I get the exit code of cmd1 in cmd1 cmd2 First  note that cmd1 exit code could be non-zero and still don t mean an error  This happens for instance in cmd   head -1  You might observe a 141  or 269 with ksh93  exit status of cmd1  but it s because cmd was interrupted by a SIGPIPE signal when head -1 terminated after having read one line  To know the exit status of the elements of a pipeline cmd1   cmd2   cmd3 a  with Z shell  zsh   The exit codes are provided in the pipestatus special array  cmd1 exit code is in  pipestatus 1   cmd3 exit code in  pipestatus 3   so that    is always the same as  pipestatus -1   b  with Bash  The exit codes are provided in the PIPESTATUS special array  cmd1 exit code is in   PIPESTATUS 0    cmd3 exit code in   PIPESTATUS 2    so that    is always the same as   PIPESTATUS  -1       For more details see Z shell

User · Answer

------------------------------------------------------------------------------   purpose  to run a command  log cmd output  exit on error   usage    set -e  do run cmd or exit  quot  cmd quot    set  e  ------------------------------------------------------------------------------ do run cmd or exit        cmd  quot    quot         do log  quot DEBUG running cmd or exit    quot  cmd  quot  quot      msg    cmd 2 gt  amp 1      export exit code           If occurred during the execution  exit with error     error msg  quot Failed to run the command            quot  cmd  quot  with the output            quot  msg  quot      quot       if    exit code -ne 0     then         do log  quot ERROR  msg quot          do log  quot FATAL  msg quot          do exit  quot  exit code quot   quot  error msg quot      else           If no errors occurred  just log the message         do log  quot DEBUG   cmdoutput     quot  msg  quot  quot      fi

User · Answer

http   cfaj freeshell org shell cus-faq-2 html 11  How do I get the exit code of cmd1 in cmd1 cmd2 First  note that cmd1 exit code could be non-zero and still don t mean an error  This happens for instance in cmd   head -1  You might observe a 141  or 269 with ksh93  exit status of cmd1  but it s because cmd was interrupted by a SIGPIPE signal when head -1 terminated after having read one line  To know the exit status of the elements of a pipeline cmd1   cmd2   cmd3 a  with Z shell  zsh   The exit codes are provided in the pipestatus special array  cmd1 exit code is in  pipestatus 1   cmd3 exit code in  pipestatus 3   so that    is always the same as  pipestatus -1   b  with Bash  The exit codes are provided in the PIPESTATUS special array  cmd1 exit code is in   PIPESTATUS 0    cmd3 exit code in   PIPESTATUS 2    so that    is always the same as   PIPESTATUS  -1       For more details see Z shell

User · Answer

If you just call exit in Bash without any parameters  it will return the exit code of the last command  Combined with OR  Bash should only invoke exit  if the previous command fails  But I haven t tested this   command1    exit  command2    exit   Bash will also store the exit code of the last command in the variable

User · Answer

set -e  is probably the easiest way to do this  Just put that before any commands in your program

User · Answer

set -e  is probably the easiest way to do this  Just put that before any commands in your program

User · Answer

After each command  the exit code can be found in the    variable so you would have something like   ls -al file ext rc     if     rc    0     then exit  rc  fi   You need to be careful of piped commands since the    only gives you the return code of the last element in the pipe so  in the code   ls -al file ext   sed  s   xx       will not return an error code if the file doesn t exist  since the sed part of the pipeline actually works  returning 0    The bash shell actually provides an array which can assist in that case  that being PIPESTATUS  This array has one element for each of the pipeline components  that you can access individually like   PIPESTATUS 0     pax gt  false   true   echo   PIPESTATUS 0   1   Note that this is getting you the result of the false command  not the entire pipeline  You can also get the entire list to process as you see fit   pax gt  false   true   false  echo   PIPESTATUS     1 0 1   If you wanted to get the largest error code from a pipeline  you could use something like   true   true   false   true   false rcs   PIPESTATUS      rc 0  for i in   rcs   do rc     i  gt   rc    i    rc    done echo  rc   This goes through each of the PIPESTATUS elements in turn  storing it in rc if it was greater than the previous rc value

User · Answer

In Bash this is easy  Just tie them together with  amp  amp   command1  amp  amp  command2  amp  amp  command3  You can also use the nested if construct  if command1    then        if command2            then                do something            else                exit        fi    else        exit fi

User · Answer

http   cfaj freeshell org shell cus-faq-2 html 11  How do I get the exit code of cmd1 in cmd1 cmd2 First  note that cmd1 exit code could be non-zero and still don t mean an error  This happens for instance in cmd   head -1  You might observe a 141  or 269 with ksh93  exit status of cmd1  but it s because cmd was interrupted by a SIGPIPE signal when head -1 terminated after having read one line  To know the exit status of the elements of a pipeline cmd1   cmd2   cmd3 a  with Z shell  zsh   The exit codes are provided in the pipestatus special array  cmd1 exit code is in  pipestatus 1   cmd3 exit code in  pipestatus 3   so that    is always the same as  pipestatus -1   b  with Bash  The exit codes are provided in the PIPESTATUS special array  cmd1 exit code is in   PIPESTATUS 0    cmd3 exit code in   PIPESTATUS 2    so that    is always the same as   PIPESTATUS  -1       For more details see Z shell

User · Answer

After each command  the exit code can be found in the    variable so you would have something like   ls -al file ext rc     if     rc    0     then exit  rc  fi   You need to be careful of piped commands since the    only gives you the return code of the last element in the pipe so  in the code   ls -al file ext   sed  s   xx       will not return an error code if the file doesn t exist  since the sed part of the pipeline actually works  returning 0    The bash shell actually provides an array which can assist in that case  that being PIPESTATUS  This array has one element for each of the pipeline components  that you can access individually like   PIPESTATUS 0     pax gt  false   true   echo   PIPESTATUS 0   1   Note that this is getting you the result of the false command  not the entire pipeline  You can also get the entire list to process as you see fit   pax gt  false   true   false  echo   PIPESTATUS     1 0 1   If you wanted to get the largest error code from a pipeline  you could use something like   true   true   false   true   false rcs   PIPESTATUS      rc 0  for i in   rcs   do rc     i  gt   rc    i    rc    done echo  rc   This goes through each of the PIPESTATUS elements in turn  storing it in rc if it was greater than the previous rc value

User · Answer

If you want to work with     you ll need to check it after each command  since    is updated after each command exits   This means that if you execute a pipeline  you ll only get the exit code of the last process in the pipeline  Another approach is to do this  set -e set -o pipefail  If you put this at the top of the shell script  it looks like Bash will take care of this for you   As a previous poster noted   quot set -e quot  will cause Bash to exit with an error on any simple command    quot set -o pipefail quot  will cause Bash to exit with an error on any command in a pipeline as well  See here or here for a little more discussion on this problem   Here is the Bash manual section on the set builtin

User · Answer

-eq 0      exit       Exit for nonzero return code

User · Answer

-eq 0      exit       Exit for nonzero return code

User · Answer

After each command  the exit code can be found in the    variable so you would have something like   ls -al file ext rc     if     rc    0     then exit  rc  fi   You need to be careful of piped commands since the    only gives you the return code of the last element in the pipe so  in the code   ls -al file ext   sed  s   xx       will not return an error code if the file doesn t exist  since the sed part of the pipeline actually works  returning 0    The bash shell actually provides an array which can assist in that case  that being PIPESTATUS  This array has one element for each of the pipeline components  that you can access individually like   PIPESTATUS 0     pax gt  false   true   echo   PIPESTATUS 0   1   Note that this is getting you the result of the false command  not the entire pipeline  You can also get the entire list to process as you see fit   pax gt  false   true   false  echo   PIPESTATUS     1 0 1   If you wanted to get the largest error code from a pipeline  you could use something like   true   true   false   true   false rcs   PIPESTATUS      rc 0  for i in   rcs   do rc     i  gt   rc    i    rc    done echo  rc   This goes through each of the PIPESTATUS elements in turn  storing it in rc if it was greater than the previous rc value

User · Answer

If you want to work with     you ll need to check it after each command  since    is updated after each command exits   This means that if you execute a pipeline  you ll only get the exit code of the last process in the pipeline  Another approach is to do this  set -e set -o pipefail  If you put this at the top of the shell script  it looks like Bash will take care of this for you   As a previous poster noted   quot set -e quot  will cause Bash to exit with an error on any simple command    quot set -o pipefail quot  will cause Bash to exit with an error on any command in a pipeline as well  See here or here for a little more discussion on this problem   Here is the Bash manual section on the set builtin

User · Answer

http   cfaj freeshell org shell cus-faq-2 html 11  How do I get the exit code of cmd1 in cmd1 cmd2 First  note that cmd1 exit code could be non-zero and still don t mean an error  This happens for instance in cmd   head -1  You might observe a 141  or 269 with ksh93  exit status of cmd1  but it s because cmd was interrupted by a SIGPIPE signal when head -1 terminated after having read one line  To know the exit status of the elements of a pipeline cmd1   cmd2   cmd3 a  with Z shell  zsh   The exit codes are provided in the pipestatus special array  cmd1 exit code is in  pipestatus 1   cmd3 exit code in  pipestatus 3   so that    is always the same as  pipestatus -1   b  with Bash  The exit codes are provided in the PIPESTATUS special array  cmd1 exit code is in   PIPESTATUS 0    cmd3 exit code in   PIPESTATUS 2    so that    is always the same as   PIPESTATUS  -1       For more details see Z shell

User · Answer

set -e  is probably the easiest way to do this  Just put that before any commands in your program

[bash] Exit Shell Script Based on Process Exit Code

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