Commands by captaincomic

Commands by captaincomic (5)

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Add page numbers to a PDF

Put this code in a bash script. The script expects the PDF file as its only parameter. It will add a header to the PDF containing the page numbers and output it to a file with the suffix "-header.pdf" Requires enscript, ps2pdf and pdftk.
This is sample output - yours may be different.
1

enscript -L1 -b'||Page $% of $=' -o- < <(for i in $(seq "$(pdftk "$1" dump_data | grep "Num" | cut -d":" -f2)"); do echo; done) | ps2pdf - | pdftk "$1" multistamp - output "${1%.pdf}-header.pdf"

captaincomic · 2012-01-27 12:26:33 10
Quick syntax highlighting with multiple output formats

On Debian/Ubuntu the pygments script is called pygmentize and can be found in the python-pygments package. For an overview of all available lexers, formatters, styles and filters use pygmentize -L Here is an example using more options pygmentize -f 256 -l sh -F whitespace:spaces=True,tabs=True -O style=borland ~/.bashrc | less -R
This is sample output - yours may be different.
0

pygmentize -l sh ~/.bashrc | less -R

captaincomic · 2012-01-27 03:27:37 4
Disable rm, use trash instead

To prevent accidental deleting of files you can disable rm with this alias. Then use the trash command from trash-cli instead.
This is sample output - yours may be different.
0

alias rm='echo "rm is disabled, use trash or /bin/rm instead."'

captaincomic · 2012-01-27 03:11:45 4
Get the first non-empty line in a text file

Use this command if your file may contain empty lines and you need to optain the first non-empty line.
This is sample output - yours may be different.
0

grep . "$f" | head -n1

captaincomic · 2012-01-27 02:58:07 7
Escape forward slashes in a variable

For example path="/etc/apt/sources.list"; echo ${path//'/'/'\/'} will print \/etc\/apt\/sources.list Show Sample Output
This is sample output - yours may be different.
```
\/etc\/apt\/sources.list
```
1

${path//'/'/'\/'}

captaincomic · 2012-01-27 02:50:01 16

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Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Extract raw URLs from a file

you can also use cut instead of awk. less powerful but probably faster. ;)

drop first column of output by piping to this

Find ulimit values of currently running process

When dealing with system resource limits like max number of processes and open files per user, it can be hard to tell exactly what's happening. The /etc/security/limits.conf file defines the ceiling for the values, but not what they currently are, while $ ulimit -a will show you the current values for your shell, and you can set them for new logins in /etc/profile and/or ~/.bashrc with a command like: $ ulimit -S -n 100000 >/dev/null 2>&1 But with the variability in when those files get read (login vs any shell startup, interactive vs non-interactive) it can be difficult to know for sure what values apply to processes that are currently running, like database or app servers. Just find the PID via "ps aux | grep programname", then look at that PID's "limits" file in /proc. Then you'll know for sure what actually applies to that process.

convert Decimal to IP from stdin

https://stackoverflow.com/questions/10768160/ip-address-converter

Fibonacci With Case

Returns the '$1'th Fibonacci number.

how to export a table in .csv file

Exports the result of query in a csv file

list block devices

Shows all block devices in a tree with descruptions of what they are.

Determine next available UID

Typical usage would be in a script that would want the next open UID in a range (in this case 500-600)

Count opening and closing braces in a string.

This function counts the opening and closing braces in a string. This is useful if you have eg long boolean expressions with many braces and you simply want to check if you didn't forget to close one.

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Follow the Tweets.

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