Been a while since I posted here, and while the following is something trivial it is nevertheless something I had to Google a bit to find out, so here goes. <\/p>\n
I have a lot of micro SD cards to which I sync my music. The cards are labelled “Card1”, “Card2”, and so on. Corresponding to these I have folders called “Card1”, “Card2”, and so on. I have a batch file that runs robocopy to copy from the folder to card. I have to specify the drive letter of the card to the batch file, but now I am being lazy and want to just double click the batch file and get it to figure out the drive letter. After all the drive with a label “CardX” will be the one I want to use. <\/p>\n
How can I get the drive letter from the label? There are many ways probably, since I like WMIC here’s how I will do it:<\/p>\n
wmic volume<\/pre>\nThis command will list all the volumes on the computer. There’s a lot of output, so a better way is to use the
\/format:list<\/code> switch to get a listed output: <\/p>\nwmic volume get \/format:list<\/pre>\nHere’s an example output for my micro SD card:<\/p>\n
Access=\r\nAutomount=TRUE\r\nAvailability=\r\nBlockSize=131072\r\nBootVolume=FALSE\r\nCapacity=62724767744\r\nCaption=E:\\\r\nCompressed=\r\nConfigManagerErrorCode=\r\nConfigManagerUserConfig=\r\nCreationClassName=\r\nDescription=\r\nDeviceID=\\\\?\\Volume{ccc55992-18dc-11e4-beaf-c417feeee1af}\\\r\nDirtyBitSet=FALSE\r\nDriveLetter=E:\r\nDriveType=2\r\nErrorCleared=\r\nErrorDescription=\r\nErrorMethodology=\r\nFileSystem=exFAT\r\nFreeSpace=4087218176\r\nIndexingEnabled=\r\nInstallDate=\r\nLabel=CARD4\r\nLastErrorCode=\r\nMaximumFileNameLength=255\r\nName=E:\\\r\nNumberOfBlocks=\r\nPageFilePresent=FALSE\r\nPNPDeviceID=\r\nPowerManagementCapabilities=\r\nPowerManagementSupported=\r\nPurpose=\r\nQuotasEnabled=\r\nQuotasIncomplete=\r\nQuotasRebuilding=\r\nSerialNumber=1721549728\r\nStatus=\r\nStatusInfo=\r\nSupportsDiskQuotas=FALSE\r\nSupportsFileBasedCompression=FALSE\r\nSystemCreationClassName=\r\nSystemName=TINTIN\r\nSystemVolume=FALSE<\/pre>\nIt’s easy to see that the
Label<\/code> property can be used to check the label. TheDriveLetter<\/code> property gives me the drive name. If I want to target removable disks only (as is my case) theDriveType<\/code> property can be used. <\/p>\nThus for instance, to filter by the label I can do:<\/p>\n
wmic volume where \"Label='Card4'\"<\/pre>\nOr to filter by both label and type I can do:<\/p>\n
wmic volume where \"Label='Card4' and DriveType=2\"<\/pre>\nTo output only the drive letter, I can use the
get<\/code> verb of WMIC:<\/p>\nC:\\Users\\rakhesh>wmic volume where \"Label='Card4' and DriveType=2\" get DriveLetter\r\nDriveLetter\r\nE:\r\n\r\nC:\\Users\\rakhesh>wmic volume where \"Label='Card4' and DriveType=2\" get DriveLetter \/format:list\r\n\r\n\r\nDriveLetter=E:<\/pre>\nThe second command is what I will use further as it returns the output in a way I know how to use. <\/p>\n
In batch files the
FOR<\/code> loop can be used to parse output and do things with it. The best place to get start with is by typinghelp for<\/code> in a command prompt to get the help text. Here’s the bit that caught my attention:<\/p>\n\n Finally, you can use the FOR \/F command to parse the output of a
\n command. You do this by making the file-set between the
\n parenthesis a back quoted string. It will be treated as a command
\n line, which is passed to a child CMD.EXE and the output is captured
\n into memory and parsed as if it was a file. So the following
\n example:<\/p>\nFOR \/F “usebackq delims==” %i IN (`set`) DO @echo %i<\/p>\n
would enumerate the environment variable names in the current
\n environment.\n<\/p><\/blockquote>\nThis looks like what I want. The
usebackq<\/code> option tellsFOR<\/code> that the text between the back-ticks –`set`<\/code> in the example above – is to be treated like a command and the output of that is to be parsed. Thedelims==<\/code> option tellsFOR<\/code> that the delimiter between parts of the output is the=<\/code> character. In case of the example above, since the output ofset<\/code> is a series of text of the formVARIABLE=VALUE<\/code>, this text will be split along the=<\/code> character and the%i<\/code> variable will be assigned the part on the left. So the snippet above will output a list ofVARIABLE<\/code>s. <\/p>\nIf I adapt that command to my command above, I have the following:<\/p>\n
FOR \/F \"usebackq delims==\" %i IN (`wmic volume where \"Label='Card4' and DriveType=2\" get DriveLetter \/format:list`) DO @echo %i<\/pre>\nOutput from the above code looks like this:<\/p>\n
ECHO is on.\r\nECHO is on.\r\nDriveLetter\r\nECHO is on.\r\nECHO is on.\r\nECHO is on.<\/pre>\nAs expected, the picks the
DriveLetter<\/code> part. What I want instead is the bit on the right hand side, so I use thetokens<\/code> option for that. I want the second token, so I usetokens=2<\/code>. I learnt about this from theFOR<\/code> help page. <\/p>\nHere’s the final command:<\/p>\n
FOR \/F \"tokens=2 usebackq delims==\" %i IN (`wmic volume where \"Label='Card4' and DriveType=2\" get DriveLetter \/format:list`) DO @echo %i<\/pre>\nThat’s it! Now to assign this to a variable I do change the
echo<\/code> to a variable assignment:<\/p>\nFOR \/F \"tokens=2 usebackq delims==\" %i IN (`wmic volume where \"Label='Card4' and DriveType=2\" get DriveLetter \/format:list`) DO set CARD_DRIVE=%i<\/pre>\nHere’s the final result in a batch file:<\/p>\n
SET \/P INP=Which card? Type digit and press ENTER: \r\nSET SOURCE=Card%INP%\r\n\r\nFOR \/F \"tokens=2 usebackq delims==\" %%i IN (`wmic volume where \"Label='%SOURCE%' and DriveType=2\" get DriveLetter \/format:list`) DO set DEST=%%i\r\n\r\nIF \"%DEST%\"==\"\" GOTO WrongCard\r\nrobocopy %SOURCE% %DEST% \r\nGOTO TheEnd\r\n\r\n:WrongCard\r\n ECHO Error: Card not found!\r\n GOTO TheEnd\r\n\r\n:TheEnd<\/pre>\n","protected":false},"excerpt":{"rendered":"Been a while since I posted here, and while the following is something trivial it is nevertheless something I had to Google a bit to find out, so here goes. I have a lot of micro SD cards to which I sync my music. The cards are labelled “Card1”, “Card2”, and so on. Corresponding to … Continue reading Find removable drive letter from label<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[102,85],"tags":[224,225,38,226],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/posts\/1380"}],"collection":[{"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/comments?post=1380"}],"version-history":[{"count":0,"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/posts\/1380\/revisions"}],"wp:attachment":[{"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/media?parent=1380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/categories?post=1380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rakhesh.com\/wp-json\/wp\/v2\/tags?post=1380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}