commands.rst

.. _linux_commands_memo:

Linux Commands Memo
===================

This is a linux command line reference for common operations.
The network commands are in a separated
:ref:`Network Commands Memo <network_commands_memo>`.


basic
-----
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   :man:`apropos` whatis%Show commands pertinent to string.
   :man:`man` -t ascii | ps2pdf - > ascii.pdf%make a pdf of a manual page
   :man:`which` command%Show full path name of command
   :man:`time` command%See how long a command takes
   :man:`time` cat%Start stopwatch. Ctrl-d to stop.

files
-----
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   ls -la > dirlist 2>&1%`Redirect`_ both stdout and stderr to a file.
   `rename`_ 's/.jpeg$/.jpg/' \*.jpeg%Mass rename with perl rename command
   :man:`rename <rename.ul>` .jpeg .jpg \*.jpeg%Mass rename with util-linux rename command
   `find`_ ./ -type f -print | `xargs`_ :coreutils:`chmod` 640%Change permissions to 640 for all files in subtree.
   `find`_ ./ -type d -print | `xargs`_ :coreutils:`chmod` 751%Change permissions to 751 for all sub-directories.
   :man:`shred` -u private.txt%delete a file from disk after securely erasing the content.

dir navigation
--------------

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   :man:`cd` -%Go to previous directory
   :man:`cd`%Go to $HOME directory
   (:man:`cd` dir && command)%Go to dir, execute command and return to current dir
   `pushd <dirstack>`_ *dir*%Put *dir* on stack so you can **popd** back to it
   `pushd <dirstack>`_ +3%Rotate the dir stack, putting third entry at top

File searching
--------------

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   :coreutils:`ls` -lt%List files by date, newest first
   :coreutils:`ls` /usr/bin | :coreutils:`pr` -T9 -W$COLUMNS%Print in 9 columns to width of terminal
   `find`_ -maxdepth 1 -type f -print0 | `xargs`_ -0 ls -lS |min2|\ block-size=1k%List files by decreasing size
   `find`_ -size +1M -ls%List files bigger than 1 Megabyte.
   `find`_ -name '\*.[ch]' | `xargs`_ grep -E 'expr'%Search 'expr' in this dir and below.
   `find`_ -type f -print0 | `xargs`_ -r0 grep -F 'example'%Search all regular files for 'example' in this dir and below
   `find`_ -maxdepth 1 -type f | `xargs`_ grep -F 'example'%Search all regular files for 'example' in this dir
   `find`_ -maxdepth 1 -type d | while read dir; do echo $dir; echo cmd2; done%Process each item with multiple commands (in while loop)
   `find`_. -xtype l%Find broken links
   `find`_ -type f ! -perm -444%Find files not readable by all (useful for web site)
   `find`_ -type d ! -perm -111%Find dirs not accessible by all (useful for web site)
   :bsdman:`locate` -r '*file*.txt'%Search cached path index for names.
   :bsdman:`locate` -r 'file[^/]*\\.txt'%Search cached path index for names. 'file' must be in last component.


disk space
----------

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   :coreutils:`ls` -lkS%Show files by size in kb, biggest first.
   :coreutils:`ls` -lt%sort by modification time, newest first
   :coreutils:`du` -sh * | :coreutils:`sort` -k1,1rh | :coreutils:`head`%Show larger directories in current dir.
   sudo :coreutils:`du` -hs /home/* | :coreutils:`sort` -k1,1h%Sort paths by increasing use
   :coreutils:`du` -ah |min2|\ max-depth=0 * | :coreutils:`sort` -k1,1rh | :coreutils:`head` -n 15%Show 15 larger directories or files in current dir.
   :coreutils:`df` -h%Show free space on mounted filesystems
   :coreutils:`df` -i%Show free inodes on mounted filesystems
   sudo :man:`sfdisk` -l /dev/sda%Show disks partitions sizes and types (MBR part)
   sudo :man:`sgdisk` -p /dev/sda%Show disks partitions sizes and types (GUID part)
   :coreutils:`dd` bs=1 seek=2TB if=/dev/null of=ext3.test%Create a large sparse test file (taking no space).
   >| file%truncate data of file or create an empty file

text handling
-------------
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   :coreutils:`tr` -dc '[:print:]' < /dev/urandom§Filter non printable characters
   echo "(33) 06.61 62-63+84" | :coreutils:`tr` -d [:blank:][:punct:]§clean a phone number string
   :coreutils:`tr` -s '[:blank:]' '\t' </proc/diskstats | :coreutils:`cut` -f4§cut fields separated by blanks
   :coreutils:`tr` -s '[:blank:]' </proc/diskstats | :coreutils:`cut` -d' ' -f4§cut fields separated by blanks
   :coreutils:`wc` -l file§count lines (``w`` words, ``-b`` bytes)
   :coreutils:`cut` -d: -f1 /etc/passwd | :coreutils:`sort`§Lists all usernames in alphabetical order.
   :coreutils:`dd` if=/dev/urandom count=1 | :coreutils:`base64` -w 0 | :coreutils:`cut` -c 1-16§generate random 16 chararacters password
   :man:`openssl` :man:`rand` -base64 16 | :coreutils:`cut` -c 1-16§generate random 16 chararacters password
   :coreutils:`tr` -dc '[:alnum:]&~#|_@=+$%*<>,?;.:/!-' < /dev/urandom | :coreutils:`head` -c${1:-16}; echo§generate random 16 chararacters password
   :man:`date` +%s | :coreutils:`sha1sum`|:coreutils:`cut` -f1 -d' '§generate new 4O alphanumeric chars password
   :coreutils:`paste` -d ',:' file1 file2 file3§Merges given files line by line
   :man:`mount` | :bsdman:`column` -t§table of mounted filesystems
   :coreutils:`join` -t'\0' -a1 -a2 file1 file2§Union of sorted files
   :coreutils:`join` -t'\0' file1 file2§Intersection of sorted files
   :coreutils:`join` -t'\0' -v2 file1 file2§Difference of sorted files
   :coreutils:`join` -t'\0' -v1 -v2 file1 file2§Symmetric Difference of sorted files
   :bsdman:`column` -s, -t <tmp.csv§pretty print csv
   :coreutils:`printf` "%03o\\n" "\'%"§octal code of ascii character ``%``
   :coreutils:`printf` "Ox%02x\\n" "\'%"§hexacimal code of ascii character ``%``
   :coreutils:`printf` "%d\\n" "\'%"§decimal code of ascii character ``%``
   :man:`iconv` -f ISO8859-1 -t UTF-8 -o file.utf8 file.txt§convert encoding
   :man:`iconv` -l§List known coded character sets
   :coreutils:`sha1sum` file§checksum of a file (use also `other sums`_: ``sha256sum``,  ``sha512sum``,  ``md5sum``)
   :coreutils:`sha1sum` -c checksumlist§check the sums against the files

encryption
----------

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   `gpg`_ -c file%Encrypt file. More commands in the :ref:`gnupg_memo`.
   `gpg`_ file.gpg%Decrypt file.
   :man:`openssl` -h%Help including available ciphers
   :man:`openssl` list-cipher-commands%long list of available ciphers
   openssl :man:`enc` -aes-256-cbc -salt -a%encrypt stdin to stdout  using 256-bit AES in CBC mode, and encode in base64
   openssl :man:`enc` -aes-256-cbc -salt -in file.txt -out file.enc%encrypt to *binary* file.enc using 256-bit AES in CBC mode
   openssl :man:`enc` -d -aes-256-cbc%decrypt binary data on stdin
   openssl :man:`enc` -d -aes-256-cbc -a -in file.enc%decrypt base64 encoded file
   openssl :man:`enc` -aes-256-cbc -salt -a -pass file:/path/to/password.txt%encrypt stdin to stdout, provide password in a file

archives and compression
------------------------

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   :man:`tar` -cjf dir.tar.bz2 dir/%Make bzip2 compressed archive of dir/
   :man:`tar` -jxf dir.tar.bz2%Extract archive (replace **j**, by **z** for gzip, or lzip)
   :man:`tar` -cxf dir.tgz |min2|\ exclude '\*.o' |min2|\ exclude '\*~' dir/
   :man:`tar` -xf dir.tgz |min2|\ to-stdout  dir/file.txt%Print file to stdout
   :man:`tar` -c dir/ | gzip | `gpg`_ -c | :man:`ssh` user\@remote 'dd of=dir.tar.gz.gpg'%Make encrypted archive of dir/ on remote machine.
   `find`_ dir/ -name '\*.txt' | :man:`tar` -c |min2|\ files-from=- | bzip2 > dir\_txt.tar.bz2%Make archive of subset of dir/ and below.
   `find`_ dir/ -name '\*.txt' | `xargs`_ :coreutils:`cp` -a |min2|\ target-directory=dir\_txt/ |min2|\ parents%Make copy of subset of dir/ and below.
   ( :man:`tar` -c /dir/to/copy ) | ( cd /where/to/ && :man:`tar` -x -p )%Copy (with permissions) copy/ dir to /where/to/ dir
   ( cd /dir/to/copy && :man:`tar` -c **.** ) | ( cd /where/to/ && :man:`tar` -x -p )%Copy (with permissions) contents of copy/ dir to /where/to/
   ( :man:`tar` -c /dir/to/copy ) | :man:`ssh` -C user\@remote 'cd /where/to/ && :man:`tar` -x -p'%Copy (with permissions) copy/ dir to remote:/where/to/ dir
   :man:`zip` -r /path/to/archive.zip dir%zip a directory
   :man:`unzip` archive.zip%extract archive
   :man:`unzip` -l archive.zip%list archive content
   :man:`unzip` archive.zip file.txt%Extract one file from archive
   :coreutils:`dd` if=/dev/vg0/vol0 of=/dev/vg1/vol1 bs=4096%Copy a partition to another one (bs must be a divider of volume blocksize)
   :coreutils:`dd` bs=1M if=/dev/sda | gzip | :man:`ssh` user\@remote 'dd of=sda.gz'%Backup harddisk to remote machine.
   :coreutils:`dd` bs=4096 if=/dev/vgsource/root_snap| :man:`ssh` -c 'chacha20-poly1305@openssh.com' rootr\@remote dd  bs=4096 of=/dev/vgremote/root_copy%copy a partition to remote machine
   :coreutils:`dd` bs=4096 if=/dev/vg0/root_snap| | :man:`ssh`-c 'chacha20-poly1305@openssh.com' root
   :man:`killall` -s USR1 dd%Ask dd to print the state of the current transfer.

process management
------------------
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   :man:`ps` axww%list all processes
   :man:`ps` axuww%list all processes and resource used
   :man:`ps` axmu%list all processes and threads
   :man:`ps` axf -o pid,args%List processes in a hierarchy.
   :man:`ps` ax -o pcpu,cpu,nice,state,cputime,args |min2|\ sort -pcpu | :man:`sed` '/^ 0.0 /d'%List processes by  decreasing cpu rate (see also :man:`top`).
   :man:`ps` ax -opid=,rss=,args= |min2|\ sort=+rss | :man:`sed` '/^\s*0\>/d' | :coreutils:`pr` -TW$COLUMNS%List processes by mem (KB) usage (see also :man:`top`).
   :man:`ps` -o user |min2|\ sort user| :coreutils:`uniq` -c| :coreutils:`sort` -n -k1%number of processes per user.
   :man:`ps` -C lighttpd -o pid=%pid of *lighttpd*.
   :man:`pgrep` light%pid of processes having *light* in their name.
   :man:`pgrep` -a daemon%pid/command-line of all processes having *daemon* in their name
   `pidof <http://linux.die.net/man/8/pidof>`_  lighttpd%pid of *lighttpd*.
   :man:`ps` uw -C lighttpd%user oriented list of process *lighttpd*.
   :man:`ps` -C firefox-bin -L -o pid,tid,pcpu,state%List all threads for a particular process.
   :man:`ps` -p 666 -o etime=%List elapsed wall time for process id 666
   :man:`ps` ew 666%show command and environment of process 666
   :coreutils:`kill` -9 1234%Send SIGKILL to process 1234
   :man:`killall` -s USR1 dd%Send signal USR1 to the dd program
   :bsdman:`pkill` -s USR1 dd%Send signal USR1 to the dd program
   :man:`pmap` 1234%Memory map of process 1234

monitoring, process admin
-------------------------
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   :coreutils:`tail` -f /var/log/messages%Monitor messages in a log file.
   :man:`less` +F /var/log/messages%Monitor messages in a log file.
   :man:`lsof` -p 666%List paths that process id 666 has open.
   :man:`lsof` /path/to/file%List processes that have specified path open.
   :man:`lsof` -u foo%Processes and files of user foo
   :man:`lsof` -u foo%Processes no of user foo
   :man:`lsof` -t -c  pcmanfm%files open by pcmanfm
   :man:`fuser` -va 22/tcp%List processes using port 22
   :man:`fuser` -va /home%List processes accessing the /home
   sudo `tcpdump`_ not port 22%Show network traffic except ssh.
   sudo `tcpdump`_ -ni eth0 'dst 192.168.1.5 and tcp and port http'%all HTTP session to 192.168.1.5.
   :man:`last` reboot%Show system reboot history.
   :man:`free` -m%Show amount of (remaining) RAM (-m displays in MB)
   :man:`watch` -n.1 'cat /proc/interrupts'%Watch changeable data continuously.
   :man:`watch` -t -n1 :man:`uptime`%Clock with system load.
   :man:`nice` *command*%Low priority *command*.
   sudo :man:`renice` 19 -p 666%Set process 666 to low scheduling priority (0<pr<20)
   sudo :man:`renice` +2 -p 666%Lower the scheduling priority.
   :man:`chrt` -i 0 *command*%Low priority command (more effective than nice)
   sudo :man:`ionice` -p 666%io class and priority of process 666. Higher priority 0
   sudo :man:`ionice`  -c3 -p 666%Sets process 666 as an idle io process.
   :man:`htop` -d 5%Better top (scrollable, tree view, lsof/strace integration, ...)
   :man:`iotop`%What's doing I/O.
   sudo :man:`iftop`%What's using the network.
   :bsdman:`vmstat` 3%monitor processes, memory, paging, block IO, traps, and cpu activity.(columns are explained in the :bsdman:`manual <vmstat>`.)
   :bsdman:`vmstat` -m%usage of kernel dynamic memory.

Users
-----
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   :man:`id` -a%Show the active user id with login and groups.
   :man:`last`%Show last logins on the system.
   :bsdman:`w`%users logged on, and their processes.
   :man:`groupadd` admin%Add group "admin"
   :man:`useradd` -c "Linus Torvald" -g admin -m linus%Add new user
   :man:`usermod` -a -G sudo linus%add group "sudo" to linus groups.
   :man:`adduser` |min2|\ uid 3333 linus%Add new user, with interactive prompt, create home dir.
   :man:`userdel` linus%Delete user linus

system information
------------------
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   :coreutils:`uname` -a%Show kernel version and system architecture.
   :coreutils:`cat` /etc/debian_version%Get Debian version
   :man:`lsb_release` -a%Full release info of any LSB distribution
   :coreutils:`cat` /etc/issue%Show name and version of distribution.
   :coreutils:`cat` /proc/partition%Show all partitions registered on the system.
   `grep`_ MemTotal /proc/meminfo%Show RAM total (see also *free*, *vmstat*)
   :coreutils:`cat` /proc/cpuinfo%Show CPU(s) info
   :man:`lscpu`%Show CPU(s) info
   :man:`lsdev`%hardware info from the /proc directory
   sudo :man:`lspci` -tv%Show PCI info
   sudo :man:`lshw`%Show hardware configuration of the machine
   sudo :man:`hwinfo`%Show hardware configuration of the machine
   :man:`lsusb` -tv%Show USB info
   :man:`mount` | :coreutils:`column` -t%List mounted fs on the system (and align output)
   `grep`_ -F capacity: /proc/acpi/battery/BAT0/info%Show state of cells in laptop battery
   :man:`dmidecode` -q | less%Display SMBIOS/DMI information
   :man:`dumpe2fs` -h /dev/part1 | `grep`_ -e '\\([mM]ount\\)\\|\\([Cc]heck\\)'%info about fs check
   sudo :man:`e2fsck` -f -v -t -C 0 /dev/part1%Check health of partition
   sudo :man:`sdparm` -C stop /dev/sdb%Stop scsi (also usb) disk
   sudo :man:`hdparm` -i /dev/sda%Show info about disk sda
   :man:`dmesg`%Detected hardware and boot messages


sed
---

See `sed manual <sed>`_ and
`sed1line <http://sed.sourceforge.net/sed1line.txt>`_.

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   ``sed -n '8,12p'``%Print lines 8 to 12
   ``sed -n '/regexp/p'``%Print lines which match regular expression
   ``sed '/regexp/d'``%Print lines which don't match regular expression
   ``sed -n '/begregexp/,/endregexp/p'``%Print section of file between two regexp
   ``sed '/begregexp/,/endregexp/d'``%Print file except section between two regexp
   ``sed '/^#/d; /^ *$/d'``%Remove comments and blank lines
   ``sed -i 's/[ \t]\*$//' file.txt``%Delete trailing space at end of lines
   ``sed -e :a -e '/^\n*$/N;/\n$/ba'``%Delete blank lines at end of file.
   ``sed -i 42d ~/.ssh/known_hosts``%Delete a particular line
   ``sed ':a; /\\$/N; s/\\\n//; ta'``%Concatenate lines with trailing ``\``
   ``sed = filename | sed 'N;s/\n/\t/'``%Put a left count number on each line of a file
   ``sed = filename | sed 'N; s/^/     /; s/ *\(.\{6,\}\)\n/\1  /'``%Put a right aligned count on each line
   ``sed 's/\x0D$//'``%Dos to unix eol
   ``sed 's/$/\\r/'``%Unix to dos eol

:wikipedia:`File attributes <chattr>`, :wikipedia:`Extended Attributes` and  :wikipedia:`ACL`
---------------------------------------------------------------------------------------------
They are three different sets of attributes that can be supported from filesytems.
For more details look at the :ref:`File attributes section <file_attributes>` and
the :ref:`ACL section <access_control_list>`.

*Note: for ext 2/3/4 fs you may need to (re)mount with "acl" or
"user_xattr" options. Or set the filesystem default with tune2fs. On
btrfs acl and xattr are enabled by default.*

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   :man:`getfacl` foo%Show ACLs for file.
   :man:`setfacl` -m u:nobody:r foo.txt%Allow a specific user to read file.
   :man:`setfacl` -x u:nobody foo.txt%Delete a specific user's rights to file.
   :man:`setfacl` |min2|\ default -m group:users:rw- dir/%Set umask for a for a specific dir.
   :bsdman:`getcap` file%Show capabilities for a program.
   :bsdman:`setcap` cap_net_raw+ep your_gtk_prog%Allow gtk program raw access to network
   :man:`getfattr` -m- -d%Show all extended attributes (includes selinux,acls,...)
   :man:`setfattr` -n "user.foo" -v "bar" .%Set arbitrary user attributes

Desktop management
------------------
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   :man:`xset` q%display X user preferences.
   :man:`xset -b`%Turn off system beep
   :man:`xset -b`%Turn on system beep
   :man:`xwininfo`%Info of the window selected by mouse click.
   :man:`xwininfo -name emacs`%Emacs window info.
   :man:`xprop`%Xserver properties of the window selected by mouse click.
   :man:`xdpyinfo`%Xserver dimension and resolution.
   :man:`wmctrl` -lG%List managed windows with their geometry.
   :man:`wmctrl` -l -x%List managed windows with their ``WM_CLASS``.
   :man:`wmctrl` -d%List desktops, current desktop has a ``*``
   :man:`wmctrl` -s 3%switch to desktop 3
   :man:`wmctrl` -a emacs%switch to  desktop containing emacs and raise it.
   :man:`wmctrl` -r emacs -t2%send emacs to third desktop
   :man:`wmctrl` -r emacs -e 0,-1,-1,756,495%resize emacs to 756x495 pixels
   :man:`xdotool` search |min2|\ onlyvisible |min2|\ class *emacs* windowsize |min2|\ usehints |percnt|\ 1 80 24%resize emacs to 80 columns x 24 lines.
   :man:`xwit` -columns 80 -rows 24 -names foo%resize  *foo* window.
   :man:`xwit` -columns 80 -rows 24 -select%select and resize a window.
   :man:`xwit` -rows 34 -columns 80 -property WM_CLASS -names emacs%resize all emacs windows.

Images manipulation
-------------------
The syntax is given for `ImageMagick`_ . If you prefer
`GraphicsMagick <http://www.graphicsmagick.org>`_ just put   ``gm`` before the
operation. The the option related to an input file comme before the file name
in GraphicsMagick and **after** in `ImageMagick`_.

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   :widths: 50, 60

   `identify <http://www.imagemagick.org/script/identify.php>`_ *photo.jpg*%information about an image file
   `convert`_ *photo.png* -resize 2048x1536 -quality 80 *photo.jpg*%resize an image
   `convert`_ *apple.jpg* -crop 128×128+50+50 *apple_crop.jpg*%crop an image
   `convert`_ *lying.jpg* -rotate 90 *standing.jpg*%rotate an image
   `convert`_ \*.jpg ouput.pdf%Create a single PDF from multiple images with `ImageMagick`_
   `import <http://www.imagemagick.org/script/import.php>`_ *snapshot.jpg*%Take a snapshot of a mouse selected desktop area.


Pdf
---
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   :man:`gs` -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=2 -dLastPage=2 -sOutputFile=page2.pdf input.pdf%Extract a page from pdf document
   :man:`pdftk` input.pdf burst%Burst a  PDF document into pages and dump its data to doc_data.txt
   :man:`pdfseparate` input.pdf p-\ |percnt|\ d.pdf%separates xx.pdf into separate pages: p-1.pdf, p-2.pdf, ...
   :man:`pdfseparate` -f 2 -l 3 input.pdf p-\ |percnt|\ d.pdf%separates from page 2 to page 3: p-2.pdf, p-3.pdf
   :man:`pdfjam` intput.pdf '2,3' |min2|\ outfile output.pdf%separates pages 2 and 3
   `qpdf`_ intput.pdf |min2|\ pages intput.pdf 1-3 |min2|\ output.pdf%separates pages 2 and 3
   :man:`gs` -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=all.pdf file1.pdf file2.pdf ...%Join many pdf files into one.
   :man:`pdftk` in1.pdf in2.pdf cat output out1.pdf%Join two pdf files
   :man:`pdfunite` in1.pdf in2.pdf out1.pdf%Join two pdf files
   :man:`pdfjam` file1.pdf '-' file2.pdf '1,2' file3.pdf '2-' |min2|\ outfile output.pdf%merge all pages of file1.pdf, page 1 and 2 of file2.pdf and all pages up from page 2 of file3.pdf
   `qpdf`_ file1.pdf |min2|\ pages file1.pdf |min2|\ pages file2.pdf 1-2 |min2|\ pages file3.pdf 2- |min2| output.pdf%merge all pages of file1.pdf, page 1 and 2 of file2.pdf and all pages up from page 2 of file3.pdf
   :man:`pdfimages` input.pdf img%extracts all images as impg-000.ppm, img-001.ppm,...
   :man:`pdfcrop` |min2|\ margins ’5 10 20 30’ input.pdf output.pdf%crop a pdf with left, top, right and bottom margins of 5, 10, 20, and 30 pt
   :man:`pdfjam` |min2|\ trim '1cm 2cm 1cm 2cm' |min2|\ clip true file1.pdf |min2|\ outfile output.pdf%crop a pdf with left, top, right and bottom margins of 1cm 2cm 1cm 2cm
   :man:`pdfjam` |min2|\ nup 2x2 input.pdf |min2|\ outfile output.pdf%recombines the pdf file to contain 4 pages per page.
   :man:`pdftk` secured.pdf input_pw *mypass* output public.pdf%save a public copy of a password protected file
   `qpdf`_ |min2|\ password=\ *mypass* |min2|\ decrypt secured.pdf public.pdf%save a public copy of a password protected file

Refs
----

-  This page is a fork of *pixelbeat*
   `command line reference <http://www.pixelbeat.org/cmdline.html>`_
   see also the `unix commands page
   <http://www.pixelbeat.org/docs/unix_commands/>`_,
   `More Linux commands <http://www.pixelbeat.org/docs/linux_commands.html>`_,
   the `programming notes <http://www.pixelbeat.org/programming/>`_,
   the `scripts <http://www.pixelbeat.org/scripts/>`_
-  Other system command memos:
   `Unix Toolbox <http://cb.vu/unixtoolbox.xhtml>`_,
   `commandlinefu <http://www.commandlinefu.com/>`_,
   `shell-fu <http://www.shell-fu.org/>`_.

.. |percnt| unicode:: 0x25 .. % sign
.. |min2| unicode:: 0x2d 0x2d .. - -
.. _convert: http://www.imagemagick.org/script/convert.php
.. _dirstack: http://www.gnu.org/software/bash/manual/html_node/Directory-Stack-Builtins.html
.. _find: http://www.gnu.org/software/findutils/manual/html_node/find_html/index.html
.. _gpg: http://www.gnupg.org/documentation/manuals/gnupg/
.. _grep: http://www.gnu.org/software/grep/manual/html_node/index.html
.. _ImageMagick: http://www.imagemagick.org
.. _other sums: https://www.gnu.org/software/coreutils/manual/html_node/Summarizing-files.html
.. _qpdf: http://qpdf.sourceforge.net/files/qpdf-manual.html#ref.using
.. _Redirect: http://www.gnu.org/software/bash/manual/bashref.html#Redirections
.. _rename: https://metacpan.org/pod/distribution/File-Rename/rename.PL
.. _rsync: http://www.samba.org/ftp/rsync/rsync.html
.. _sed: http://www.gnu.org/software/sed/manual/sed.html
.. _tcpdump: http://www.tcpdump.org/tcpdump_man.html
.. _sed: http://www.gnu.org/software/sed/manual/sed.html
.. _wget: http://www.gnu.org/software/wget/manual/wget.html
.. _xargs: http://www.gnu.org/software/findutils/manual/html_node/find_html/xargs-options.html
..
   TODO: Complete with other commands from http://cb.vu/unixtoolbox.xhtml
   Use |percnt| to include % in a command.
   Use the commands in https://wiki.archlinux.org/index.php/Core_utilities.