jpegoptim Flags

jpegoptim -help
jpegoptim v1.4.4 Copyright (c) 1996-2016, Timo Kokkonen
Usage: jpegoptim [options]

-d, --dest= specify alternative destination directory for
optimized files (default is to overwrite originals)
-f, --force force optimization
-h, --help display this help and exit
-m, --max=
set maximum image quality factor (disables lossless
optimization mode, which is by default on)
Valid quality values: 0 - 100
-n, --noaction don't really optimize files, just print results
-S, --size=
Try to optimize file to given size (disables lossless
optimization mode). Target size is specified either in
kilo bytes (1 - n) or as percentage (1% - 99%)
-T, --threshold= keep old file if the gain is below a threshold (%)
-b, --csv print progress info in CSV format
-o, --overwrite overwrite target file even if it exists (meaningful
only when used with -d, --dest option)
-p, --preserve preserve file timestamps
-P, --preserve-perms
preserve original file permissions by overwriting it
-q, --quiet quiet mode
-t, --totals print totals after processing all files
-v, --verbose enable verbose mode (positively chatty)
-V, --version print program version

-s, --strip-all strip all markers from output file
--strip-none do not strip any markers
--strip-com strip Comment markers from output file
--strip-exif strip Exif markers from output file
--strip-iptc strip IPTC/Photoshop (APP13) markers from output file
--strip-icc strip ICC profile markers from output file
--strip-xmp strip XMP markers markers from output file

--all-normal force all output files to be non-progressive
--all-progressive force all output files to be progressive
--stdout send output to standard output (instead of a file)
--stdin read input from standard input (instead of a file)

ulimit flags, commands, and help

help ulimit
ulimit: ulimit [-SHacdefilmnpqrstuvx] [limit]
Modify shell resource limits.

Provides control over the resources available to the shell and processes
it creates, on systems that allow such control.

-S use the `soft' resource limit
-H use the `hard' resource limit
-a all current limits are reported
-b the socket buffer size
-c the maximum size of core files created
-d the maximum size of a process's data segment
-e the maximum scheduling priority (`nice')
-f the maximum size of files written by the shell and its children
-i the maximum number of pending signals
-l the maximum size a process may lock into memory
-m the maximum resident set size
-n the maximum number of open file descriptors
-p the pipe buffer size
-q the maximum number of bytes in POSIX message queues
-r the maximum real-time scheduling priority
-s the maximum stack size
-t the maximum amount of cpu time in seconds
-u the maximum number of user processes
-v the size of virtual memory
-x the maximum number of file locks

If LIMIT is given, it is the new value of the specified resource; the
special LIMIT values `soft', `hard', and `unlimited' stand for the
current soft limit, the current hard limit, and no limit, respectively.
Otherwise, the current value of the specified resource is printed. If
no option is given, then -f is assumed.

Values are in 1024-byte increments, except for -t, which is in seconds,
-p, which is in increments of 512 bytes, and -u, which is an unscaled
number of processes.

Exit Status:
Returns success unless an invalid option is supplied or an error occurs.

gzip flags

gzip -help
Apple gzip 264.50.1
usage: gzip [-123456789acdfhklLNnqrtVv] [-S .suffix] [ [ ...]]
-1 --fast fastest (worst) compression
-2 .. -8 set compression level
-9 --best best (slowest) compression
-c --stdout write to stdout, keep original files
-d --decompress uncompress files
-f --force force overwriting & compress links
-h --help display this help
-k --keep don't delete input files during operation
-l --list list compressed file contents
-N --name save or restore original file name and time stamp
-n --no-name don't save original file name or time stamp
-q --quiet output no warnings
-r --recursive recursively compress files in directories
-S .suf use suffix .suf instead of .gz
--suffix .suf
-t --test test compressed file
-V --version display program version
-v --verbose print extra statistics

wget Help – commands, usage, flags, examples

GNU Wget 1.15, a non-interactive network retriever.
Usage: wget [OPTION]... [URL]...

Mandatory arguments to long options are mandatory for short options too.

-V, --version display the version of Wget and exit.
-h, --help print this help.
-b, --background go to background after startup.
-e, --execute=COMMAND execute a `.wgetrc'-style command.

Logging and input file:
-o, --output-file=FILE log messages to FILE.
-a, --append-output=FILE append messages to FILE.
-d, --debug print lots of debugging information.
-q, --quiet quiet (no output).
-v, --verbose be verbose (this is the default).
-nv, --no-verbose turn off verboseness, without being quiet.
--report-speed=TYPE Output bandwidth as TYPE. TYPE can be bits.
-i, --input-file=FILE download URLs found in local or external FILE.
-F, --force-html treat input file as HTML.
-B, --base=URL resolves HTML input-file links (-i -F)
relative to URL.
--config=FILE Specify config file to use.

-t, --tries=NUMBER set number of retries to NUMBER (0 unlimits).
--retry-connrefused retry even if connection is refused.
-O, --output-document=FILE write documents to FILE.
-nc, --no-clobber skip downloads that would download to
existing files (overwriting them).
-c, --continue resume getting a partially-downloaded file.
--progress=TYPE select progress gauge type.
-N, --timestamping don't re-retrieve files unless newer than
--no-use-server-timestamps don't set the local file's timestamp by
the one on the server.
-S, --server-response print server response.
--spider don't download anything.
-T, --timeout=SECONDS set all timeout values to SECONDS.
--dns-timeout=SECS set the DNS lookup timeout to SECS.
--connect-timeout=SECS set the connect timeout to SECS.
--read-timeout=SECS set the read timeout to SECS.
-w, --wait=SECONDS wait SECONDS between retrievals.
--waitretry=SECONDS wait 1..SECONDS between retries of a retrieval.
--random-wait wait from 0.5*WAIT...1.5*WAIT secs between retrievals.
--no-proxy explicitly turn off proxy.
-Q, --quota=NUMBER set retrieval quota to NUMBER.
--bind-address=ADDRESS bind to ADDRESS (hostname or IP) on local host.
--limit-rate=RATE limit download rate to RATE.
--no-dns-cache disable caching DNS lookups.
--restrict-file-names=OS restrict chars in file names to ones OS allows.
--ignore-case ignore case when matching files/directories.
-4, --inet4-only connect only to IPv4 addresses.
-6, --inet6-only connect only to IPv6 addresses.
--prefer-family=FAMILY connect first to addresses of specified family,
one of IPv6, IPv4, or none.
--user=USER set both ftp and http user to USER.
--password=PASS set both ftp and http password to PASS.
--ask-password prompt for passwords.
--no-iri turn off IRI support.
--local-encoding=ENC use ENC as the local encoding for IRIs.
--remote-encoding=ENC use ENC as the default remote encoding.
--unlink remove file before clobber.

-nd, --no-directories don't create directories.
-x, --force-directories force creation of directories.
-nH, --no-host-directories don't create host directories.
--protocol-directories use protocol name in directories.
-P, --directory-prefix=PREFIX save files to PREFIX/...
--cut-dirs=NUMBER ignore NUMBER remote directory components.

HTTP options:
--http-user=USER set http user to USER.
--http-password=PASS set http password to PASS.
--no-cache disallow server-cached data.
--default-page=NAME Change the default page name (normally
this is `index.html'.).
-E, --adjust-extension save HTML/CSS documents with proper extensions.
--ignore-length ignore `Content-Length' header field.
--header=STRING insert STRING among the headers.
--max-redirect maximum redirections allowed per page.
--proxy-user=USER set USER as proxy username.
--proxy-password=PASS set PASS as proxy password.
--referer=URL include `Referer: URL' header in HTTP request.
--save-headers save the HTTP headers to file.
-U, --user-agent=AGENT identify as AGENT instead of Wget/VERSION.
--no-http-keep-alive disable HTTP keep-alive (persistent connections).
--no-cookies don't use cookies.
--load-cookies=FILE load cookies from FILE before session.
--save-cookies=FILE save cookies to FILE after session.
--keep-session-cookies load and save session (non-permanent) cookies.
--post-data=STRING use the POST method; send STRING as the data.
--post-file=FILE use the POST method; send contents of FILE.
--method=HTTPMethod use method "HTTPMethod" in the header.
--body-data=STRING Send STRING as data. --method MUST be set.
--body-file=FILE Send contents of FILE. --method MUST be set.
--content-disposition honor the Content-Disposition header when
choosing local file names (EXPERIMENTAL).
--content-on-error output the received content on server errors.
--auth-no-challenge send Basic HTTP authentication information
without first waiting for the server's

HTTPS (SSL/TLS) options:
--secure-protocol=PR choose secure protocol, one of auto, SSLv2,
SSLv3, TLSv1 and PFS.
--https-only only follow secure HTTPS links
--no-check-certificate don't validate the server's certificate.
--certificate=FILE client certificate file.
--certificate-type=TYPE client certificate type, PEM or DER.
--private-key=FILE private key file.
--private-key-type=TYPE private key type, PEM or DER.
--ca-certificate=FILE file with the bundle of CA's.
--ca-directory=DIR directory where hash list of CA's is stored.
--random-file=FILE file with random data for seeding the SSL PRNG.
--egd-file=FILE file naming the EGD socket with random data.

FTP options:
--ftp-user=USER set ftp user to USER.
--ftp-password=PASS set ftp password to PASS.
--no-remove-listing don't remove `.listing' files.
--no-glob turn off FTP file name globbing.
--no-passive-ftp disable the "passive" transfer mode.
--preserve-permissions preserve remote file permissions.
--retr-symlinks when recursing, get linked-to files (not dir).

WARC options:
--warc-file=FILENAME save request/response data to a .warc.gz file.
--warc-header=STRING insert STRING into the warcinfo record.
--warc-max-size=NUMBER set maximum size of WARC files to NUMBER.
--warc-cdx write CDX index files.
--warc-dedup=FILENAME do not store records listed in this CDX file.
--no-warc-compression do not compress WARC files with GZIP.
--no-warc-digests do not calculate SHA1 digests.
--no-warc-keep-log do not store the log file in a WARC record.
--warc-tempdir=DIRECTORY location for temporary files created by the
WARC writer.

Recursive download:
-r, --recursive specify recursive download.
-l, --level=NUMBER maximum recursion depth (inf or 0 for infinite).
--delete-after delete files locally after downloading them.
-k, --convert-links make links in downloaded HTML or CSS point to
local files.
--backups=N before writing file X, rotate up to N backup files.
-K, --backup-converted before converting file X, back up as X.orig.
-m, --mirror shortcut for -N -r -l inf --no-remove-listing.
-p, --page-requisites get all images, etc. needed to display HTML page.
--strict-comments turn on strict (SGML) handling of HTML comments.

Recursive accept/reject:
-A, --accept=LIST comma-separated list of accepted extensions.
-R, --reject=LIST comma-separated list of rejected extensions.
--accept-regex=REGEX regex matching accepted URLs.
--reject-regex=REGEX regex matching rejected URLs.
--regex-type=TYPE regex type (posix).
-D, --domains=LIST comma-separated list of accepted domains.
--exclude-domains=LIST comma-separated list of rejected domains.
--follow-ftp follow FTP links from HTML documents.
--follow-tags=LIST comma-separated list of followed HTML tags.
--ignore-tags=LIST comma-separated list of ignored HTML tags.
-H, --span-hosts go to foreign hosts when recursive.
-L, --relative follow relative links only.
-I, --include-directories=LIST list of allowed directories.
--trust-server-names use the name specified by the redirection
url last component.
-X, --exclude-directories=LIST list of excluded directories.
-np, --no-parent don't ascend to the parent directory.

Mail bug reports and suggestions to .

Flags / Options for pngcrush

Here’s the list of flags / options for pngcrush-1.8.11 – January 2017 Version.

A couple common flags are “-ow” to overwrite the original file with the crushed file and “-brute” to ‘brute-force’ all optimization methods (slowest, but most compression)

pngcrush [options except for -e -d] infile.png outfile.png
pngcrush -e ext [other options] file.png ...
pngcrush -d dir/ [other options] file.png ...
pngcrush -ow [other options] file.png [tempfile.png]
pngcrush -n -v file.png ...


-bail (bail out of trial when size exceeds best size found)
-blacken (zero samples underlying fully-transparent pixels)
-brute (use brute-force: try 148 different methods)
-c color_type of output file [0, 2, 4, or 6]
-check (check CRC and ADLER32 checksums)
-d directory_name/ (where output files will go)
-e extension (used for creating output filename)
-f user_filter [0-5] for specified method
-fix (salvage PNG with otherwise fatal conditions)
-force (write output even if IDAT is larger)
-g gamma (float or fixed*100000, e.g., 0.45455 or 45455)
-huffman (use only zlib strategy 2, Huffman-only)
-iccp length "Profile Name" iccp_file
-itxt b[efore_IDAT]|a[fter_IDAT] "keyword"
-keep chunk_name
-l zlib_compression_level [0-9] for specified method
-loco ("loco crush" truecolor PNGs)
-m method [1 through 150]
-max maximum_IDAT_size [default 524288L]
-mng (write a new MNG, do not crush embedded PNGs)
-n (no save; doesn't do compression or write output PNG)
-new (Use new default settings (-reduce))
-newtimestamp (Reset file modification time [default])
-nobail (do not bail out early from trial -- see "-bail")
-nocheck (do not check CRC and ADLER32 checksums)
-nofilecheck (do not check for infile.png == outfile.png)
-noforce (default; do not write output when IDAT is larger)
-nolimits (turns off limits on width, height, cache, malloc)
-noreduce (turns off all "-reduce" operations)
-noreduce_palette (turns off "-reduce_palette" operation)
-old (Use old default settings (no -reduce))
-oldtimestamp (Do not reset file modification time)
-ow (Overwrite)
-q (quiet) suppresses console output except for warnings
-reduce (do lossless color-type or bit-depth reduction)
-rem chunkname (or "alla" or "allb")
-replace_gamma gamma (float or fixed*100000) even if it is present.
-res resolution in dpi
-rle (use only zlib strategy 3, RLE-only)
-s (silent) suppresses console output including warnings
-save (keep all copy-unsafe PNG chunks)
-speed Avoid the AVG and PAETH filters, for decoding speed
-srgb [0, 1, 2, or 3]
-ster [0 or 1]
-text b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
-trns_array n trns[0] trns[1] .. trns[n-1]
-trns index red green blue gray
-v (display more detailed information)
-version (display the pngcrush version)
-warn (only show warnings)
-w compression_window_size [32, 16, 8, 4, 2, 1, 512]
-z zlib_strategy [0, 1, 2, or 3] for specified method
-zmem zlib_compression_mem_level [1-9, default 9]
-zitxt b|a "keyword" "lcode" "tkey" "text"
-ztxt b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
-h (help and legal notices)
-p (pause)

These notes were also printed with the info statement on the program.

| Copyright (C) 1998-2002, 2006-2016 Glenn Randers-Pehrson
| Portions Copyright (C) 2005 Greg Roelofs
| This is a free, open-source program. Permission is irrevocably
| granted to everyone to use this version of pngcrush without
| payment of any fee.
| Executable name is pngcrush
| It was built with bundled libpng-1.6.28
| and is running with bundled libpng-1.6.28
| Copyright (C) 1998-2004, 2006-2016 Glenn Randers-Pehrson,
| Copyright (C) 1996, 1997 Andreas Dilger,
| Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
| and bundled zlib-1.2.11, Copyright (C) 1995-2017,
| Jean-loup Gailly and Mark Adler,
| and using “clock()”.
| It was compiled with gcc version 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1).

If you have modified this source, you may insert additional notices
immediately after this sentence.
Copyright (C) 1998-2002, 2006-2016 Glenn Randers-Pehrson
Portions Copyright (C) 2005 Greg Roelofs

DISCLAIMER: The pngcrush computer program is supplied “AS IS”.
The Author disclaims all warranties, expressed or implied, including,
without limitation, the warranties of merchantability and of fitness
for any purpose. The Author assumes no liability for direct, indirect,
incidental, special, exemplary, or consequential damages, which may
result from the use of the computer program, even if advised of the
possibility of such damage. There is no warranty against interference
with your enjoyment of the computer program or against infringement.
There is no warranty that my efforts or the computer program will
fulfill any of your particular purposes or needs. This computer
program is provided with all faults, and the entire risk of satisfactory
quality, performance, accuracy, and effort is with the user.

LICENSE: Permission is hereby irrevocably granted to everyone to use,
copy, modify, and distribute this computer program, or portions hereof,
purpose, without payment of any fee, subject to the following

1. The origin of this binary or source code must not be misrepresented.

2. Altered versions must be plainly marked as such and must not be
misrepresented as being the original binary or source.

3. The Copyright notice, disclaimer, and license may not be removed
or altered from any source, binary, or altered source distribution.