amavisd-new (8)      - Interface between MTA and virus scanner/content filters
Apache2::Filter (3pm) - Perl API for Apache 2.0 Filtering
Apache2::FilterRec (3pm) - Perl API for manipulating the Apache filter record
BIO_f_base64 (3ssl)  - base64 BIO filter
BIO_f_cipher (3ssl)  - cipher BIO filter
BIO_f_md (3ssl)      - message digest BIO filter
BIO_f_null (3ssl)    - null filter
BIO_get_cipher_ctx (3ssl) - cipher BIO filter
BIO_get_cipher_status (3ssl) - cipher BIO filter
BIO_get_md (3ssl)    - message digest BIO filter
BIO_get_md_ctx (3ssl) - message digest BIO filter
BIO_new_CMS (3ssl)   - CMS streaming filter BIO
BIO_set_cipher (3ssl) - cipher BIO filter
BIO_set_md (3ssl)    - message digest BIO filter
bpf_prog_create (9)  - create an unattached filter
bpf_prog_create_from_user (9) - create an unattached filter from user buffer
btrfs-find-root (8)  - filter to find btrfs root
bzless (1)           - file perusal filter for crt viewing of bzip2 compresse...
bzmore (1)           - file perusal filter for crt viewing of bzip2 compresse...
c++filt (1)          - Demangle C++ and Java symbols.
col (1)              - filter reverse line feeds from input
colcrt (1)           - filter nroff output for CRT previewing
Data::Dump::Filtered (3pm) - Pretty printing with filtering
dbilogstrip (1p)     - filter to normalize DBI trace logs for diff'ing
DBM_Filter (3perl)   - - Filter DBM keys/values
DBM_Filter::compress (3perl) - filter for DBM_Filter
DBM_Filter::encode (3perl) - filter for DBM_Filter
DBM_Filter::int32 (3perl) - filter for DBM_Filter
DBM_Filter::null (3perl) - filter for DBM_Filter
DBM_Filter::utf8 (3perl) - filter for DBM_Filter
dnsfilter (1)        - reverse-resolves IP addresses, converting them to host...
enum_ieee80211_filter_flags (9) - hardware filter flags
estfxasis (1)        - hyperestraier filter programs
estfxfilter (1)      - hyperestraier filter programs
estfxmantotxt (1)    - hyperestraier filter programs
estfxmsotohtml (1)   - hyperestraier filter programs
estfxpdftohtml (1)   - hyperestraier filter programs
Filter::Simple (3perl) - Simplified source filtering
Filter::Util::Call (3perl) - Perl Source Filter Utility Module
funzip (1)           - filter for extracting from a ZIP archive in a pipe
git-filter-branch (1) - Rewrite branches
HTML::Filter (3pm)   - Filter HTML text through the parser
ip6tables (8)        - administration tool for IPv4/IPv6 packet filtering and...
iptables (8)         - administration tool for IPv4/IPv6 packet filtering and...
Mail::Filter (3pm)   - Filter mail through multiple subroutines
Mason::Filters::Standard (3pm) - Standard filters
Mason::Manual::Filters (3pm) - Content filters in Mason
Method::Signatures::Simple (3pm) - Basic method declarations with signatures,...
more (1)             - file perusal filter for crt viewing
msgfilter (1)        - edit translations of message catalog
pam_filter (8)       - PAM filter module
pcap-filter (7)      - packet filter syntax
perldbmfilter (1)    - Perl DBM Filters
perlfilter (1)       - Source Filters
Pod::Parser (3perl)  - base class for creating POD filters and translators
postfix-add-filter (8) - add filter service to Postfix master.cf
rps_may_expire_flow (9) - check whether an RFS hardware filter may be removed
sed (1)              - stream editor for filtering and transforming text
selinux_netfilter_context_path (3) - These functions return the paths to the ...
sk_attach_filter (9) - attach a socket filter
sk_filter_trim_cap (9) - run a packet through a socket filter
spamassassin (1p)    - extensible email filter used to identify spam
spamassassin-run (1p) - simple front-end filtering script for SpamAssassin
spamassassin-run (3pm) - simple front-end filtering script for SpamAssassin
svndumpfilter (1)    - Filter a subversion repository 'dumpfile'.
tc-ematch (8)        - extended matches for use with "basic" or "flow" filters
tc-tbf (8)           - Token Bucket Filter
x86_64-linux-gnu-c++filt (1) - Demangle C++ and Java symbols.
xtables-multi (8)    - xtables multi-link binary for netfilter's iptables and...
zless (1)            - file perusal filter for crt viewing of compressed text
zmore (1)            - file perusal filter for crt viewing of compressed text