Execute a shell function with timeout

Question

Why would this work  timeout 10s echo  foo bar    foo bar   but this wouldn t  function echoFooBar     echo  foo bar     echoFooBar   foo bar  timeout 10s echoFooBar   timeout  failed to run command  echoFooBar   No such file or directory   and how can I make it work

User · Answer

This function uses only builtins

Maybe consider evaling "$*" instead of running $@ directly depending on your needs
It starts a job with the command string specified after the first arg that is the timeout value and monitors the job pid
It checks every 1 seconds, bash supports timeouts down to 0.01 so that can be tweaked
Also if your script needs stdin, read should rely on a dedicated fd (exec {tofd}<> <(:))
Also you might want to tweak the kill signal (the one inside the loop) which is default to -15, you might want -9

## forking is evil
timeout() {
    to=$1; shift
    $@ & local wp=$! start=0
     while kill -0 $wp; do
        read -t 1
        start=$((start+1))
        if [ $start -ge $to ]; then
            kill $wp && break
        fi
    done
}

User · Answer

function foo        for i in  1  100       do          echo  i            sleep 1      done     cat  lt   foo     Will work  timeout 3 cat  lt   foo     Will Work  timeout 3 cat  lt   foo     sort   Wont work  As sort will fail  cat  lt   timeout 3 cat  lt   foo       sort -r   Will Work

User · Answer

Putting my comment to Tiago Lopo s answer into more readable form   I think it s more readable to impose a timeout on the most recent subshell  this way we don t need to eval a string and the whole script can be highlighted as shell by your favourite editor  I simply put the commands after the subshell with eval has spawned into a shell-function  tested with zsh  but should work with bash     timeout child          trap --    SIGTERM     child        timeout  1                   sleep  timeout             kill  child        amp      wait  child     Example usage     while true  do echo -n    sleep 0 1  done   amp  timeout child 2  And this way it also works with a shell function  if it runs in the background     print dots           while true      do          sleep 0 1          echo -n        done        gt  print dots  amp  timeout child 2   1  21725   3  21727                      1     21725 terminated  print dots   3     21727 done         sleep  timeout  kill  child

User · Answer

You can create a function which would allow you to do the same as timeout but also for other functions   function run cmd        cmd   1   timeout   2       grep -qP    d     lt  lt  lt   timeout    timeout 10                 eval   cmd   amp          child            trap --    SIGTERM                                   sleep  timeout                 kill  child 2 gt   dev null             amp               wait  child           And could run as below   run cmd  echoFooBar  10   Note  The solution came from one of my questions  Elegant solution to implement timeout for bash commands and functions

User · Answer

As Douglas Leeder said you need a separate process for timeout to signal to  Workaround by exporting function to subshells and running subshell manually   export -f echoFooBar timeout 10s bash -c echoFooBar

User · Answer

There s an inline alternative also launching a subprocess of bash shell     timeout 10s bash  lt  lt EOT function echoFooBar     echo foo    echoFooBar sleep 20 EOT

User · Answer

timeout is a command - so it is executing in a subprocess of your bash shell  Therefore it has no access to your functions defined in your current shell   The command timeout is given is executed as a subprocess of timeout - a grand-child process of your shell   You might be confused because echo is both a shell built-in and a separate command   What you can do is put your function in it s own script file  chmod it to be executable  then execute it with timeout   Alternatively fork  executing your function in a sub-shell - and in the original process  monitor the progress  killing the subprocess if it takes too long

User · Answer

This one liner will exit your Bash session after 10s    TMOUT 10  amp  amp  echo  foo bar

User · Answer

I have a slight modification of  Tiago Lopo s answer that can handle commands with multiple arguments  I ve also tested TauPan s solution  but it does not work if you use it multiple times in a script  while Tiago s does   function timeout cmd      local arr   local cmd   local timeout    arr               timeout  first arg     cmd  the other args   timeout    arr 0      cmd      arr    1               eval    cmd       amp      child         echo  child   child      trap --    SIGTERM                     sleep   timeout        kill   child  2 gt   dev null         amp           wait   child          Here s a fully functional script thant you can use to test the function above       test timeout sh -h Usage    test timeout sh  -n   -r REPEAT   -s SLEEP TIME   -t TIMEOUT    test timeout sh -h  Test timeout cmd function   Options    -n              Dry run  do not actually sleep     -r REPEAT       Reapeat everything multiple times  default  1     -s SLEEP TIME   Sleep for SLEEP TIME seconds  default  5     -t TIMEOUT      Timeout after TIMEOUT seconds  default  no timeout     For example you cnal launch like this       test timeout sh -r 2 -s 5 -t 3 Try no  1   - Set timeout to  3 child  2540     - gt  retval  143     - gt  The command timed out Try no  2   - Set timeout to  3 child  2593     - gt  retval  143     - gt  The command timed out Done       usr bin env bash   shellcheck disable SC2128 SOURCED false  amp  amp      0      BASH SOURCE       SOURCED true  if    SOURCED  then   set -euo pipefail   IFS    n t  fi                       helpers function check posint       local re    0-9       local mynum   1    local option   2     if        mynum      re      then       echo -n  Error in option   option      gt  amp 2        echo  must be a positive integer  got  mynum    gt  amp 2       exit 1   fi    if       mynum  -gt 0     then       echo  Error in option   option   must be positive  got  mynum    gt  amp 2       exit 1   fi                        end  helpers                       usage function short usage         gt  amp 2 echo    Usage    test timeout sh  -n   -r REPEAT   -s SLEEP TIME   -t TIMEOUT    test timeout sh -h         function usage         gt  amp 2 short usage       gt  amp 2 echo     Test timeout cmd function   Options    -n              Dry run  do not actually sleep     -r REPEAT       Reapeat everything multiple times  default  1     -s SLEEP TIME   Sleep for SLEEP TIME seconds  default  5     -t TIMEOUT      Timeout after TIMEOUT seconds  default  no timeout                             end  usage  help flag false dryrun flag false SLEEP TIME 5 TIMEOUT -1 REPEAT 1  while getopts   hnr s t   opt  do   case  opt in     h        help flag true                  n        dryrun flag true              r        check posint   OPTARG   -r         REPEAT   OPTARG               s        check posint   OPTARG   -s         SLEEP TIME   OPTARG               t        check posint   OPTARG   -t         TIMEOUT   OPTARG                           gt  amp 2 echo  Error  Invalid option  - OPTARG            gt  amp 2 echo  Try -h to get help         short usage       exit 1                         gt  amp 2 echo  Error Option - OPTARG requires an argument            gt  amp 2 echo  Try -h to get help         short usage       exit 1            esac done  if  help flag  then   usage   exit 0 fi                       utils if  dryrun flag  then   function wrap run           echo -en   dry run   t          echo            else   function wrap run             fi    Execute a shell function with timeout   https   stackoverflow com a 24416732 2377454 function timeout cmd      local arr   local cmd   local timeout    arr               timeout  first arg     cmd  the other args   timeout    arr 0      cmd      arr    1               eval    cmd       amp      child         echo  child   child      trap --    SIGTERM                     sleep   timeout        kill   child  2 gt   dev null         amp           wait   child                              function sleep func       local secs   local waitsec    waitsec 1   secs     1     while     secs  -gt 0    do    echo -ne   secs 033 0K r     sleep   waitsec     secs    secs-waitsec     done     command   wrap run              sleep func     SLEEP TIME               for i in   seq 1   REPEAT    do   echo  Try no   i     if     TIMEOUT  -gt 0    then     echo    - Set timeout to   TIMEOUT      set  e     timeout cmd   TIMEOUT     command          retval          set -e      echo      - gt  retval   retval        check if  retval   128     SIGTERM     15      if        retval   128    -eq 15     then       echo      - gt  The command timed out      fi   else     echo    - No timeout         command          retval        fi done  echo  Done    exit 0

User · Answer

if you just want to add timeout as an additional option for the entire existing script  you can make it test for the timeout-option  and then make it call it self recursively without that option   example sh      bin bash if     1      -t     then   timeout 1m  0  2 else    the original script   echo  1   sleep 2m   echo YAWN    fi   running this script without timeout      example sh -other option   -other option                               YAWN      running it with a one minute timeout      example sh -t -other option   -other option

[bash] Execute a shell function with timeout

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