How to check command line parameter in bat file

Question

My OS is Windows Vista   I need to have a   bat  file where I need to check if user enters any command-line parameter or not    If does then if the parameter equals to -b then I will do something otherwise I will flag  Invalid input   If user does not enter any command-line parameter then I will do something  I have created following  bat file  It works for -b and not-equal to -b cases - but it fails when user does not pass any command-line parameter   I always get error   GOTO was unexpected at this time    Can anyone tell me what am I doing wrong here     ECHO OFF CLS ECHO   IF   1        GOTO BLANK  IF  1   -b  GOTO SPECIFIC  IF NOT  1   -b  GOTO UNKNOWN   SPECIFIC  ECHO SPECIFIC  GOTO DONE   BLANK  ECHO No Parameter  GOTO DONE   UNKNOWN  ECHO Unknown Option  GOTO DONE   DONE  ECHO Done

User · Answer

The short answer - use square brackets   if   1      goto  blank   or  when you need to handle quoted args  see the Edit below    if    1      goto  blank   Why  you might ask  Well  just as Jeremiah Willcock mentioned  http   ss64 com nt if html - they use that  OK  but what s wrong with the quotes   Again  short answer  they are  magical  - sometimes double  double  quotes get converted to a single  double  quote  And they need to match  for a start   Consider this little script    rem argq bat  echo off   loop  if   1      goto  done echo  1 shift goto  loop   done echo Done    Let s test it   C   gt  argq bla bla bla bla Done    Seems to work  But now  lets switch to second gear   C   gt  argq  bla bla  bla       was unexpected at this time    Boom This didn t evaluate to true  neither did it evaluate to false  The script DIED  If you were supposed to turn off the reactor somewhere down the line  well - tough luck  You now will die like Harry Daghlian   You may think - OK  the arguments can t contain quotes  If they do  this happens  Wrong Here s some consolation   C   gt  argq   bla bla     bla bla   Done    Oh yeah  Don t worry - sometimes this will work   Let s try another script    rem args bat  echo off   loop  if   1      goto  done echo  1 shift goto  loop   done echo Done    You can test yourself  that it works OK for the above cases  This is logical - quotes have nothing to do with brackets  so there s no magic here  But what about spicing the args up with brackets   D   gt args  bla bla   bla bla  Done   D   gt args  bla bla   bla bla  Done    No luck there  The brackets just can t choke cmd exe s parser   Let s go back to the evil quotes for a moment  The problem was there  when the argument ended with a quote   D   gt argq  bla1 bla2  bla2       was unexpected at this time    What if I pass just   D   gt argq bla2  The syntax of the command is incorrect    The script won t run at all  Same for args bat   D   gt args bla2  The syntax of the command is incorrect    But what do I get  when the number of  -characters  matches   i e  - is even   in such a case   D   gt args bla2   bla3 bla2   bla3 Done    NICE - I hope you learned something about how  bat files split their command line arguments  HINT   It s not exactly like in bash   The above argument contains a space  But the quotes are not stripped automatically   And argq  How does it react to that  Predictably   D   gt argq bla2   bla3  bla3      was unexpected at this time    So - think before you say   Know what  Just use quotes   Because  to me  this looks nicer     Edit  Recently  there were comments about this answer - well  sqare brackets  can t handle  passing quoted arguments and treating them just as if they weren t quoted   The syntax   if    1              Is not some newly found virtue of the double quotes  but a display of a neat feature of stripping quotes from the argument variable  if the first and last character is a double quote   This  technology  works just as well with square brackets   if    1              It was a useful thing to point this out  so I also upvote the new answer   Finally  double quote fans  does an argument of the form    exist in your book  or is it blank  Just askin

User · Answer

Actually  all the other answers have flaws  The most reliable way is   IF    1    -b   GOTO SPECIFIC  ELSE  GOTO UNKNOWN    Detailed Explanation   Using   1    -b  will flat out crash if passing argument with spaces and quotes  This is the least reliable method   IF   1    -b   GOTO SPECIFIC  ELSE  GOTO UNKNOWN   C   gt  run bat  a b   b     -b  was unexpected at this time    Using   1    -b  is better because it will not crash with spaces and quotes  but it will not match if the argument is surrounded by quotes   IF   1    -b   GOTO SPECIFIC  ELSE  GOTO UNKNOWN   C   gt  run bat  -b    does not match  and jumps to UNKNOWN instead of SPECIFIC    Using    1    -b  is the most reliable    1 will strip off surrounding quotes if they exist  So it works with and without quotes  and also with no args   IF    1    -b   GOTO SPECIFIC  ELSE  GOTO UNKNOWN   C   gt  run bat C   gt  run bat -b C   gt  run bat  -b  C   gt  run bat  a b    all of the above tests work correctly

User · Answer

I ve been struggling recently with the implementation of complex parameter switches in a batch file so here is the result of my research  None of the provided answers are fully safe  examples     1    -   will not match if the parameter is enclosed in quotes  needed for file names etc   or will crash if the parameter is in quotes and has spaces  again often seen in file names    ECHO OFF SETLOCAL echo  echo starting parameter test    echo  rem echo First parameter is  1 if   1    -    echo Condition is true  param  1  else  echo Condition is false  param  1  C   gt test bat -   starting parameter test     Condition is true  param -   C   gt test bat  -    starting parameter test     Condition is false  param  -     Any combination with square brackets   1    -   or    1    -   will fail in case the parameter has spaces within quotes    ECHO OFF SETLOCAL  echo  echo starting parameter test    echo  echo First parameter is  1 if    1    -    echo Condition is true  param  1  else  echo Condition is false  param  1   C   gt test bat  long file name   starting parameter test     First parameter is  long file name  file was unexpected at this time    The proposed safest solution    1    -   will crash with a complex parameter that includes text outside the quotes and text with spaces within the quotes    ECHO OFF SETLOCAL  echo  echo starting parameter test    echo  echo First parameter is  1 if    1    -    echo Condition is true  param  1  else  echo Condition is false  param  1   C   gt test bat -source  long file name   starting parameter test     First parameter is -source  long file name  file was unexpected at this time    The only way to ensure all above scenarios are covered is to use EnableDelayedExpansion and to pass the parameters by reference  not by value  using variables  Then even the most complex scenario will work fine    ECHO OFF SETLOCAL EnableDelayedExpansion echo  echo starting parameter test    echo  echo First parameter is  1    we assign the parameter to a variable to pass by reference with delayed expansion set  var1   1  echo var1 is  var1     we assign the value to compare with to a second variable to pass by reference with delayed expansion set  var2 -source  c  app images  image png  echo var2 is  var2  if   var1      var2    echo Condition is true  param  var1   else  echo Condition is false  param  var1   C   gt test bat -source  c  app images  image png  starting parameter test     First parameter is -source  c  app images  image png var1 is -source  c  app images  image png var2 is -source  c  app images  image png Condition is true  param -source  c  app images  image png  C   gt test bat -source  c  app images  image1 png  starting parameter test     First parameter is -source  c  app images  image1 png var1 is -source  c  app images  image1 png var2 is -source  c  app images  image png Condition is false  param -source  c  app images  image1 png  C   gt test bat -source  c  app images image png   starting parameter test     First parameter is -source  c  app images image png  var1 is -source  c  app images image png  var2 is -source  c  app images  image png Condition is false  param -source  c  app images image png

User · Answer

Look at http   ss64 com nt if html for an answer  the command is IF   1      GOTO NO ARGUMENT or similar

User · Answer

You are comparing strings   If an arguments are omitted   1 expands to a blank so the commands become IF    -b  GOTO SPECIFIC for example  which is a syntax error    Wrap your strings in quotes  or square brackets    REM this is ok IF   1        GOTO BLANK  REM I d recommend using quotes exclusively IF   1    -b  GOTO SPECIFIC  IF NOT   1    -b  GOTO UNKNOWN

User · Answer

You need to check for the parameter being blank  if    1      goto blank  Once you ve done that  then do an if else switch on -b   if    1    -b   goto specific  else goto unknown  Surrounding the parameters with quotes makes checking for things like blank empty missing parameters easier      ensures double quotes are stripped if they were on the command line argument

User · Answer

In addition to the other answers  which I subscribe  you may consider using the  I switch of the IF command          the  I switch  if specified  says to do case insensitive string compares     it may be of help if you want to give case insensitive flexibility to your users to specify the parameters   IF  I   1    -b  GOTO SPECIFIC

[windows] How to check command line parameter in ".bat" file?

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