xargs
Is a very useful program to take a list and run commands against that list.
Here is a really straightforward example of using xargs,
- -t will show you what xargs is about to execute before it executes it.
- -n1 limits the arguments passed by the directory to pass one argument, in this case one file name at a time.
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Tin-Phams-iMac:PC tinpham$ ls | xargs -t -n1 md5
md5 planetary.doc
MD5 (bash) = ab5970d50d67bcafe5c554387f76534e
md5 Superman.jpg
MD5 (cat) = cdefa50d737dfcf8dc57886ea1a758c4
Tin-Phams-iMac:bin tinpham$
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Search & Replace inside of Files
Try to memorize this command,
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find [folder] -type f | xargs -I {} grep -li "text" {} | xargs perl -pi -e 's/[text_to_search_for]/[text_to_search_for]/g'
find [folder] -type f {search the specified folder for all files, returns full path of each file}
| xargs -I {} grep -li "[text]" {} {piped into xargs to grep for all files containing specified text ignoring case}
| xargs perl -pi -e 's/[text_to_search_for]/[text_to_replace_with]/g' {pipe list of files and search/replace with specified text} |
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More details should be added for this xargs command or if possible rewrite it in a way that is more clear. |
Disk Management
List directories from largest to smallest at the top level only.
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du -sk * | sort |
Long Running Processes
Other Useful Commands
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Detailed Articles
Useful One Off Recipes
Disk Management
List directories from largest to smallest at the top level only. On older system h will not work and you must use k.
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du -sh * | sort |
Long Running Processes
Look for long running processes,
Information
Last
Last searches back through the file /var/log/wtmp (or the file designated by the -f flag) and displays a list of all users logged in (and out) since that file was created.
Lastb
Lastb is the same as last, except that by default it shows a log of the file /var/log/btmp, which contains all the bad login attempts.
Quck String Manipulation
Quick reference of manipulating standout,
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echo "some_file_name.txt" | tr "_" " " # result will be "some file name.txt"
paste oldName.txt newName.txt > runMe.txt # connects line by line to contents of both files together |
Integrity Checking
MD5
Check if a file is corrupt,
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# On Ubuntu
md5sum /path/to/file
# On Solaris
digest -a md5 -v /path/to/file |