Commands tagged exit code (1)

  • Use meaningful exit codes change "source" to "cat" to view output instead of assigning Show Sample Output

    source <(egrep '^#define EX_.*' /usr/include/sysexits.h | sed -e 's/#define/declare -r/g' | sed 's/\//#/g' | sed -e 's/\s\{1,\}/ /g' | sed -e 's/ \([0-9]\)/\=\1/'g )
    fishdaemon · 2012-09-21 13:30:37 0

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Reads a CD/DVD and creates an dvdisaster iso image with the advanced RS02 method.

quick and dirty formatting for HTML code
Finds all the closing tags in a HTML document via non-greedy regex and adds a linefeed for easier reading/editing . sed -i.bak -r 's_(/[^>]*?>)_\1\n_g' filename.html . This will save a copy of filename.html as filename.html.bak and then add the linefeeds to the original file

Create a backup of the file.
It will create a backup of the filename. The advantage is that if you list the folder the backups will be sorted by date. The command works on any unix in bash.

remove recursively all txt files with number of lines less than 10

Backticks are evil
This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes: $ program1 $(program2 $(program3 $(program4))) versus $ program1 `program2 \`program3 \`program4\`\`` Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.

For finding out if something is listening on a port and if so what the daemon is.

To print a specific line from a file
You can get one specific line during any procedure. Very interesting to be used when you know what line you want.

Efficient count files in directory (no recursion)
$ time perl -e 'if(opendir D,"."){@a=readdir D;print $#a - 1,"\n"}' 205413 real 0m0.497s user 0m0.220s sys 0m0.268s $ time { ls |wc -l; } 205413 real 0m3.776s user 0m3.340s sys 0m0.424s ********* ** EDIT: turns out this perl liner is mostly masturbation. this is slightly faster: $ find . -maxdepth 1 | wc -l sh-3.2$ time { find . -maxdepth 1|wc -l; } 205414 real 0m0.456s user 0m0.116s sys 0m0.328s ** EDIT: now a slightly faster perl version $ perl -e 'if(opendir D,"."){++$c foreach readdir D}print $c-1,"\n"' sh-3.2$ time perl -e 'if(opendir D,"."){++$c foreach readdir D}print $c-1,"\n"' 205414 real 0m0.415s user 0m0.176s sys 0m0.232s

Create cheap and easy index.html file
If your admin has disabled Apache's directory index feature but you want to have a cheap way to enable it for one folder, this command will just create an index.html file with a link to each file in the directory (including the index.html file, which is not ideal but makes the command much simpler). The HTML isn't even remotely compliant, but it could easily be improved on. Also, the command needs to be run each time a file is added or removed to update the index.html file.

Convert camelCase to underscores (camel_case)
Useful for switching over someone else's coding style who uses camelCase notation to your style using all lowercase with underscores.

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