bashoneliners.com

Explanation

• -r make a search recursively;
• -n print line numbers;
• -H is not need, is default;

Explanation

• curl read "man curl" if you need to info like using cookies,etc. you can also use wget
• -L follow redirects
• -v be verbose
• -F an input field
• value= the name of the input field
• @myfile the file you want uploaded
• "http://domain.tld/whatever.php" the url that will take the file

Explanation

• -s, --summarize; display only a total for each argument
• -c, --total; produce a grand total
• -x, --one-file-system; skip directories on different file systems
• -h, --human-readable; print sizes in human readable format (e.g., 1K 234M 2G)

Explanation

rsync works by comparing files on the local and remote machine and only sending those parts of the file that have changed. The normal way compression works, it results in everything after the modification changing, meaning lots of data ends up going over the network when you try to rsync compressed files.

The --rsyncable option to gzip changes the compression scheme so that modifications to the input file only affect the part of the file where they're located. This allows rsync to work its magic.

In this one-liner, the z option to tar calls gzip, which recognizes and uses any options specified in the GZIP environment variable.

Explanation

ps2pdf is a script that comes with Ghostscript - despite the name, it can accept PDF files as input, not just postscript files.

Explanation

-c option of du prints the total size of the arguments

Explanation

cat -n will number all lines of a file.

Explanation

The POSIX-standard comm utility can do this also.

• -2 suppresses lines from the second argument (file1)
• -3 suppresses lines appearing in both files

Explanation

• -f is to specify a file with the list of patterns: file1
• -F is to treat the patterns fixed strings, without using regular expressions
• -x is to match exactly the whole line
• -v is to select non-matching lines

The result is effectively the same as:

diff file1 file2 | grep '^>' | sed -e s/..//

Explanation

at 07:30 tomorrow schedules a job for 7:30 AM the next day, running whatever command or script is fed to it as standard input. The format for specifying time and date is rather flexible. http://tinyurl.com/ibmdwat

echo 'play alarmclock.wav 2>/dev/null' | feeds the play alarmclock.wav command to at, while 2>/dev/null causes the text output of play to be thrown away (we are only interested in the alarm sound).

Explanation

EndNote?! I know but sometimes we have windows users as friends

Explanation

pdftk is the PDF Toolkit

input.pdf is the input file.

cat 2-4 7 9-10 concatenate (combine) pages 2,3,4,7,9,10 of input.pdf.

output output.pdf the resulting pdf file containing the above pages.

Explanation

In the example above, find and display every file in /etc containing the string nameserver with the corresponding line, including line number, sample output:

/etc/ppp/ip-up.d/0dns-up:9:# Rev. Dec 22 1999 to put dynamic nameservers last.

/etc/ppp/ip-up.d/0dns-up:23:# nameservers given by the administrator. Those for which 'Dynamic' was chosen

/etc/ppp/ip-up.d/0dns-up:24:# are empty. 0dns-up fills in the nameservers when pppd gets them from the

/etc/ppp/ip-up.d/0dns-up:26:# 'search' or 'domain' directives or additional nameservers. Read the

/etc/ppp/ip-up.d/0dns-up:77:# nameserver lines to the temp file.

Explanation

*Requires PV (pipe viewer) if you want to monitor throughput; otherwise you can leave out the pv pipe.

Transparently decompresses an arbitrary .gz file (does not have to be a tar) and re-compresses it to bzip2, which has better compression and error recovery. Echoes error messages to a file named logfile.txt in your home directory.

NOTE: The original .gz file will NOT be deleted. If you want to save space, you will have to delete it manually.

Explanation

Creates a 500MB blank file and times how long it takes to finish writing the entire thing to disk (sync)

time the entire dd + sync operation, and then remove the temporary file

Explanation

Recursively remove all empty sub-directories from a directory tree using just find. No need for tac (-depth does that), no need for xargs as the directory contents changes on each call to rmdir. We're not reliant on the rmdir command deleting just empty dirs, -empty does that.

Explanation

• SQL: SELECT COUNT(x), x FROM y GROUP BY x ORDER BY count DESC;
• BASH: a temp var for the last sort: $A=$(
• the file you want: FILE=/var/log/myfile.log
• dump the file to a stream: cat $FILE |
• cut out the bits you want to count: perl -p -e 's/.*,([A-Z]+)[\:\+].*/$1/g' |
• get a unique list: sort -u |
• for each line/value in the stream do stuff: while read line; do
• dump all lines matching the current value to an inner stream: grep "$line" $FILE |
• count them: wc -l |
• clean up the output of wc and drop the value on stdout: perl -p -e 's/[^0-9]+//g';
• drop the current value to stdout: echo -e "\t$line";
• finish per value operations on the outer stream: done;
• finish output to the temp var: );
• dump the temp var to a pipe: echo "$A" |
• sort the list numerically in reverse: sort -nr

Explanation

Replace input.pdf and output.pdf with the original PDF name and the new compressed version's file name respectively. The key to this is the PDFSETTINGS option which can be tuned for various levels of compression. For scanned text documents, I find the ebook setting works well enough for most purposes but you can experiment with the options below.

• -dPDFSETTINGS=/screen (screen-view-only quality, 72 dpi images)
• -dPDFSETTINGS=/ebook (low quality, 150 dpi images)
• -dPDFSETTINGS=/printer (high quality, 300 dpi images)
• -dPDFSETTINGS=/prepress (high quality, color preserving, 300 dpi imgs) '-dPDFSETTINGS=/default (almost identical to /screen)'

Explanation

Note: replace /home with the location you want to search

Source: http://linuxcommando.blogspot.com/2008/09/how-to-find-and-delete-all-hard-links.html

Explanation

• The perl regex pattern m/\w+/g will match consecutive non-word characters, resulting in a list of all the words in the source string
• map("$_\n", @list) transforms a list, appending a new-line at the end of each element
• tr A-Z a-z transforms uppercase letters to lowercase
• In awk, length($1) == 4 {print} means: for lines matching the filter condition "length of the first column is 4", execute the block of code, in this case simply print

Explanation

Free PDF editing software might become more and more available, but this method has been working for a long time, and likely will continue to do so.

Explanation

• It will break lines longer than 80 characters at appropriate white spaces to make them less than 80 characters long.
• The -s flag will collapse multiple consecutive white spaces into one, or at the end of a sentence a double space.

Explanation

• pushd, popd and dirs are bash builtins, you can read about them with help dirs
• bash keeps a stack of "remembered" directories, and this stack can be manipulated with the pushd and popd builtins, and displayed with the dirs builtin
• pushd will put the current directory on top of the directory stack. So, if you need to change to a different directory temporarily and you know that eventually you will want to come back to where you are, it is better to change directory with pushd instead of cd. While working on the temporary task you can change directories with cd several times, and in the end when you want to come back to where you started from, you can simply do popd.

Explanation

The git archive command basically creates a tar file. The one-liner is to create a directory instead, without an intermediate tar file. The tar command above will untar the output of git archive into the directory specified with the -C flag. The directory must exist before you run this command.

Explanation

If you have a root access to the database, a drop database + create database is easiest. This script is useful in situations where you don't have root access to the database.

First prepare a file my.cnf to store database credentials so you don't have to enter on the command line:

[client]

database=dbname

user=dbuser

password=dbpass

host=dbhost

Make sure to protect this file with chmod go-rwx.

The one-liner will execute show tables on the database to list all tables. Then the while loop reads each table name line by line and executes a drop table command.