How to conditionally take action if FINDSTR fails to find a string

Question

I have a batch file as follows   CD C  MyFolder findstr  c  stringToCheck  fileToCheck bat IF NOT XCOPY  C  OtherFolder fileToCheck bat   C  MyFolder   s  y   I am getting an error   C  OtherFolder fileToCheck bat  was unexpected at this time   when trying to execute this   Please let me know what I am doing wrong

User · Answer

In DOS Windows Batch most commands return an exitCode  called  errorlevel   that is a value that customarily is equal to zero if the command ends correctly  or a number greater than zero if ends because an error  with greater numbers for greater errors  hence the name    There are a couple methods to check that value  but the original one is   IF ERRORLEVEL value command   Previous IF test if the errorlevel returned by the previous command was GREATER THAN OR EQUAL the given value and  if this is true  execute the command  For example   verify bad-param if errorlevel 1 echo Errorlevel is greater than or equal 1 echo The value of errorlevel is   ERRORLEVEL    Findstr command return 0 if the string was found and 1 if not   CD C  MyFolder findstr  c  stringToCheck  fileToCheck bat IF ERRORLEVEL 1 XCOPY  C  OtherFolder fileToCheck bat   C  MyFolder   s  y   Previous code will copy the file if the string was NOT found in the file   CD C  MyFolder findstr  c  stringToCheck  fileToCheck bat IF NOT ERRORLEVEL 1 XCOPY  C  OtherFolder fileToCheck bat   C  MyFolder   s  y   Previous code copy the file if the string was found  Try this   findstr  string  file if errorlevel 1       echo String NOT found      else       echo String found

User · Answer

I tried to get this working using FINDSTR  but for some reason my  debugging  command always output an error level of 0   ECHO  ERRORLEVEL    My workaround is to use Grep from Cygwin  which outputs the right errorlevel  it will give an errorlevel greater than 0  if a string is not found   dir c    tib  gt out 2 gt  gt  amp 1 grep  1 File s   out IF  ERRORLEVEL  NEQ 0  Run other commands  ELSE  Run Errorlevel 0 commands    Cygwin s grep will also output errorlevel 2 if the file is not found  Here s the hash from my version   C  temp temp grep --version grep  GNU grep  2 4 2  C  cygwin64 bin md5sum grep exe c0a50e9c731955628ab66235d10cea23  grep exe  C  cygwin64 bin sha1sum grep exe ff43a335bbec71cfe99ce8d5cb4e7c1ecdb3db5c  grep exe

User · Answer

You are not evaluating a condition for the IF  I am guessing you want to not copy if you find stringToCheck in fileToCheck  You need to do something like  code untested but you get the idea    CD C  MyFolder findstr  c  stringToCheck  fileToCheck bat IF NOT ERRORLEVEL 0 XCOPY  C  OtherFolder fileToCheck bat   C  MyFolder   s  y   EDIT by dbenham The above test is WRONG  it always evaluates to FALSE  The correct test is IF ERRORLEVEL 1 XCOPY      Update  I can t test the code  but I am not sure what return value findstr actually returns if it doesn t find anything  You might have to do something like   CD C  MyFolder findstr  c  stringToCheck  fileToCheck bat  gt  tempfindoutput txt set  p FINDOUTPUT   lt  tempfindoutput txt IF   FINDOUTPUT       XCOPY  C  OtherFolder fileToCheck bat   C  MyFolder   s  y del tempfindoutput txt

User · Answer

I presume you want to copy C  OtherFolder fileToCheck bat to C  MyFolder if the existing file in C  MyFolder is either missing entirely  or if it is missing  stringToCheck     FINDSTR sets ERRORLEVEL to 0 if the string is found  to 1 if it is not  It also sets errorlevel to 1 if the file is missing  It also prints out each line that matches  Since you are trying to use it as a condition  I presume you don t need or want to see any of the output  The 1st thing I would suggest is to redirect both the normal and error output to nul using  gt nul 2 gt  amp 1   Solution 1  mostly the same as previous answers   You can use IF ERRORRLEVEL N to check if the errorlevel is    N  Or you can use IF NOT ERRORLEVEL N to check if errorlevel is  lt  N  In your case you want the former   findstr  c  stringToCheck   c  MyFolder fileToCheck bat   gt nul 2 gt  amp 1 if errorlevel 1 xcopy  C  OtherFolder fileToCheck bat   c  MyFolder    Solution 2  You can test for a specific value of errorlevel by using  ERRORLEVEL   You can probably check if the value is equal to 1  but it might be safer to check if the value is not equal to 0  since it is only set to 0 if the file exists and it contains the string   findstr  c  stringToCheck   c  MyFolder fileToCheck bat   gt nul 2 gt  amp 1 if not  errorlevel     0 xcopy  C  OtherFolder fileToCheck bat   c  MyFolder    or  findstr  c  stringToCheck   c  MyFolder fileToCheck bat   gt nul 2 gt  amp 1 if  errorlevel  neq 0 xcopy  C  OtherFolder fileToCheck bat   c  MyFolder    Solution 3  There is a very compact syntax to conditionally execute a command based on the success or failure of the previous command  cmd1  amp  amp  cmd2    cmd3 which means execute cmd2 if cmd1 was successful  errorlevel 0   else execute cmd3 if cmd1 failed  errorlevel lt  0   You can use  amp  amp  alone  or    alone  All the commands need to be on the same line  If you need to conditionally execute multiple commands you can use multiple lines by adding parentheses  cmd1  amp  amp       cmd2    cmd3           cmd4    cmd5     So for your case  all you need is  findstr  c  stringToCheck   c  MyFolder fileToCheck bat   gt nul 2 gt  amp 1    xcopy  C  OtherFolder fileToCheck bat   c  MyFolder    But beware - the    will respond to the return code of the last command executed  In my earlier pseudo code the    will obviously fire if cmd1 fails  but it will also fire if cmd1 succeeds but then cmd3 fails   So if your success block ends with a command that may fail  then you should append a harmless command that is guaranteed to succeed  I like to use  CALL    which is harmless  and always succeeds  It also is handy that it sets the ERRORLEVEL to 0  There is a corollary  CALL  that always fails and sets ERRORLEVEL to 1

[windows] How to conditionally take action if FINDSTR fails to find a string

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