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TCL exec error on proc

TCL exec error on proc

TCL exec error on proc


I can run [catch {exec cmake --version} result] without problems, but I cannot run it from following function in a tcl script:

proc RunCommand {myCommand} {
if {[catch {exec $myCommand} result]} {
puts stderr $result
return TCL_ERROR

RunCommand {cmake --version}

couldn't execute "cmake --version": no such file or directory

what I am missing here? Appreciate helps.

Thank you.

Kind regards

RE: TCL exec error on proc

Actually it is a problem to use variable for a command. The question is really how to set a variable for shell commands. For example, the following will always generate an error:

set myshellcommand "cmake --version"

if {[catch {exec $myshellcommand}] result} {
return TCL_ERROR

RE: TCL exec error on proc

Instead of using


exec $my_cmd 
try rather to use command pipeline


open "|$my_cmd" 

You need probably something like this:


proc run_command_exception {my_cmd} {
  # try to open and catch the error
  set rc [catch {set f [open "|$my_cmd" "r"]} res]
  # if the command was succesfull then process command output
  if {$rc == 0} {
    while {[gets $f line] != -1} {
      # print line
      puts $line
    # try to close and catch the error
    set rc [catch {close $f} res]

  # if an error occured then print it
  if {$rc != 0} {
    puts stderr "* $res" 

  # return code
  return $rc

# *** main ***
set my_cmd "cmd.exe /c DIR C:\\\"Program Files\"\\G* /B"
set my_cmd "no_such_command"
set my_cmd "ls -la"
set my_cmd "make --version"
set my_cmd "make --kk"

puts "* Now executing the Command '$my_cmd':\n"
set res [run_command_exception $my_cmd]
puts "* Command Result: \$res = '$res'" 

I tried it with several commands and it seems to work.

RE: TCL exec error on proc

Thank you very much mikrom, it indeed works.


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