{"id":6491,"date":"2008-03-23T15:22:31","date_gmt":"2008-03-23T15:22:31","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/powershell\/2008\/03\/23\/select-string-and-grep\/"},"modified":"2019-02-18T13:16:06","modified_gmt":"2019-02-18T20:16:06","slug":"select-string-and-grep","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/powershell\/select-string-and-grep\/","title":{"rendered":"Select-String and Grep"},"content":{"rendered":"

Dustin Marx has a blog entry where he compares Unix\/Linux, PowerShell and DOS commands<\/a>.  In it he says, "If there is one Unix command I would love to have in PowerShell, it is the grep command with its regular expression support.<\/em>"  Well Dustin, your wish is our command.  Select-String command to be precise:<\/p>\n

PS> Get-Help Select-String<\/strong><\/font><\/p>\n

NAME
    Select-String <\/font><\/p>\n

SYNOPSIS
    Identifies patterns in strings. <\/font><\/p>\n

SYNTAX
    Select-String [-pattern] <string[]> -inputObject <psobject> [-include <stri
    ng[]>] [-exclude <string[]>] [-simpleMatch] [-caseSensitive] [-quiet] [-lis
    t] [<CommonParameters>] <\/font><\/p>\n

    Select-String [-pattern] <string[]> [-path] <string[]> [-include <string[]>
    ] [-exclude <string[]>] [-simpleMatch] [-caseSensitive] [-quiet] [-list] [<
    CommonParameters>] <\/font><\/p>\n

DETAILED DESCRIPTION
    Identifies patterns in strings. By default, Select-String interprets the va
    lue of the Pattern parameter as a regular expression and matches input agai
    nst it. To learn more about regular expressions in Windows PowerShell, type
     get-help about_regular_expression. You can suppress the regular expression
     match by using the SimpleMatch parameter. A simple match attempts to find
    the string specified in the Pattern parameter as a substring of the input. <\/font><\/p>\n

    The cmdlet makes it easy to search string content from files. It includes a
     Path parameter that supports wildcards and when that parameter is used, th
    e contents of the referenced files are retrieved and matched against the va
    lue of the Pattern parameter. <\/font><\/p>\n

    Output from the cmdlet is, by default, a MatchInfo object which includes de
    tailed information about the matches. The information is most useful when t
    he input to the cmdlet is retrieved from files. The object includes propert
    ies like Filename and Line, which have the value ‘InputStream’ when the inp
    ut was not from a file. You can use the Quiet parameter to suppress the out
    put of MatchInfo objects. In that case, the resulting output becomes a bool
    ean value that is true if a match occurred and false otherwise. <\/font><\/p>\n

    When matching file content, you can use the List parameter to stop after th
    e first match in each input file. You should use this parameter if you only
     require a single match, because it will result in faster matching commands.<\/font><\/p>\n

<\/font><\/p>\n

There are a ton of great scenarios but here are some of the more common usages:<\/p>\n

PS> dir . -recurse |%{ "`n*** $($_.name)"; cat $_} <\/strong><\/font><\/p>\n

*** animals.txt
dog
cat
horse
cow <\/font><\/p>\n

*** fruit.txt
orange
apple
cherry <\/font><\/p>\n

*** trees.txt
Elm
Maple
Oak
Dogwood
Apple <\/font><\/p>\n

PS> Set-Alias ss Select-String <\/strong><\/font><\/p>\n

PS> ss Dog *<\/strong> <\/font><\/p>\n

animals.txt:1:dog
trees.txt:4:Dogwood <\/font><\/p>\n

PS> ss Dog * -CaseSensitive <\/strong><\/font><\/p>\n

trees.txt:4:Dogwood <\/font><\/p>\n

PS> ss ^[cd]o *<\/strong> <\/font><\/p>\n

animals.txt:1:dog
animals.txt:4:cow
trees.txt:4:Dogwood <\/font><\/p>\n

PS> ss ^[cd]o -path * -Exclude *an*.txt<\/strong> <\/font><\/p>\n

trees.txt:4:Dogwood<\/font><\/p>\n

 <\/p>\n

We’ve expanded Select-String in the next version with a number of additional functions.  One of my favorites is -Context which allows you to specify the number of lines  you want displayed before and after a match.  Check it out:<\/p>\n

PS> ss oak * <\/strong><\/font><\/p>\n

trees.txt:3:Oak <\/font><\/p>\n

PS> ss oak * -Context 1,0<\/strong> <\/font><\/p>\n

  trees.txt:2:Maple
> trees.txt:3:Oak <\/font><\/p>\n

PS> ss oak * -Context 0,1<\/strong> <\/font><\/p>\n

> trees.txt:3:Oak
  trees.txt:4:Dogwood <\/font><\/p>\n

PS> ss oak * -Context 2,1<\/strong> <\/font><\/p>\n

  trees.txt:1:Elm
  trees.txt:2:Maple
> trees.txt:3:Oak
  trees.txt:4:Dogwood <\/font><\/p>\n

And last but not least, this is PowerShell so of course we are not going to just emit text, we emit objects which <\/p>\n

PS> ss dog * |fl * <\/strong><\/font><\/p>\n

IgnoreCase : True
LineNumber : 1
Line       : dog
Filename   : animals.txt
Path       : C:\\temp\\ss\\animals.txt
Pattern    : dog <\/font><\/p>\n

IgnoreCase : True
LineNumber : 4
Line       : Dogwood
Filename   : trees.txt
Path       : C:\\temp\\ss\\trees.txt
Pattern    : dog<\/font><\/p>\n

We should have produced an alias from grep to Select-String.<\/p>\n

Enjoy!<\/p>\n

Jeffrey Snover [MSFT]
Windows Management Partner Architect
Visit the Windows PowerShell Team blog at:    http:\/\/blogs.msdn.com\/PowerShell<\/a>
Visit the Windows PowerShell ScriptCenter at:  http:\/\/www.microsoft.com\/technet\/scriptcenter\/hubs\/msh.mspx<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Dustin Marx has a blog entry where he compares Unix\/Linux, PowerShell and DOS commands.  In it he says, "If there is one Unix command I would love to have in PowerShell, it is the grep command with its regular expression support."  Well Dustin, your wish is our command.  Select-String command to be precise: PS> Get-Help […]<\/p>\n","protected":false},"author":600,"featured_media":13641,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[189,16],"class_list":["post-6491","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-powershell","tag-grep","tag-select-string"],"acf":[],"blog_post_summary":"

Dustin Marx has a blog entry where he compares Unix\/Linux, PowerShell and DOS commands.  In it he says, "If there is one Unix command I would love to have in PowerShell, it is the grep command with its regular expression support."  Well Dustin, your wish is our command.  Select-String command to be precise: PS> Get-Help […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/6491","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/users\/600"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/comments?post=6491"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/6491\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media\/13641"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media?parent=6491"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/categories?post=6491"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/tags?post=6491"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}