TIFFWriteDirectory(3tiff), TIFFRewriteDirectory(3tiff),
 TIFFCheckpointDirectory(3tiff) - write the current directory in an open TIFF
 file

 TIFFWriteEncodedStrip(3tiff), TIFFWritedEncodedStrip(3tiff) - compress and
 write a strip of data to an open TIFF file

 TIFFWriteEncodedTile(3tiff), TIFFWritedEncodedTile(3tiff) - compress and
 write a tile of data to an open TIFF file

 TIFFWriteRawStrip(3tiff) - write a strip of raw data to an open TIFF file

 TIFFWriteRawTile(3tiff) - write a tile of raw data to an open TIFF file

 TIFFWriteScanline(3tiff) - write a scanline to an open TIFF file

 TIFFWriteTile(3tiff) - encode and write a tile of data to an open TIFF file

 font2c(1) - Write PostScript Type 0 or Type 1 font as C code

 zipnote(1) - write the comments in zipfile to stdout, edit comments and rename
 files in zipfile

 VOP_BWRITE(9) - write a file system buffer

 VOP_GETPAGES(9), VOP_PUTPAGES(9) - read or write VM pages from a file

 VOP_READ(9), VOP_WRITE(9) - read or write a file

 VOP_STRATEGY(9) - read or write a file system buffer

 aio_write(2) - asynchronous write to a file (REALTIME)

 bread(3), bwrite(3) - read and write blocks of a UFS file system

 bsdlabel(8) - read and write BSD label

 bzero(3) - write zeroes to a byte string

 cgread(3), cgread1(3), cgwrite1(3) - read/write cylinder groups of UFS disks

 echo(1) - write arguments to the standard output

 fdwrite(1) - format and write floppy disks

 fifolog_create(1) - Initialize storage for fifolog .br fifolog_write Write data
 to fifolog .br fifolog_read Seek and extract data from fifolog

 form_post(3) - write or erase forms from associated subwindows

 g_read_data(9), g_write_data(9) - read/write data from/to GEOM consumer

 kvm_read(3), kvm_write(3) - read or write kernel virtual memory

 lseek(2) - reposition read/write file offset

 memset(3) - write a byte to byte string

 menu_post(3) - write or erase menus from associated subwindows

 pax(1) - read and write file archives and copy directory hierarchies

 pmc_read(3), pmc_rw(3), pmc_write(3) - read and write hardware performace
 counters

 pthread_rwlock_destroy(3) - destroy a read/write lock

 pthread_rwlock_init(3) - initialize a read/write lock

 pthread_rwlock_rdlock(3), pthread_rwlock_tryrdlock(3) - acquire a
 read/write lock for reading

 pthread_rwlock_timedrdlock(3) - acquire a read-write lock for reading or give up
 after a specified period

 pthread_rwlock_timedwrlock(3) - acquire a read-write lock for writing or give up
 after a specified period

 pthread_rwlock_unlock(3) - release a read/write lock

 pthread_rwlock_wrlock(3), pthread_rwlock_trywrlock(3) - acquire a
 read/write lock for writing

 pthread_rwlockattr_destroy(3) - destroy a read/write lock

 pthread_rwlockattr_init(3) - initialize a read/write lock

 rpc.rwalld(8) - write messages to users currently logged in server

 sbread(3), sbwrite(3) - read and write superblocks of a UFS file system

 scr_dump(3), scr_restore(3), scr_init(3), scr_set(3) - read (write) a curses
 screen from (to) a file

 sunlabel(8) - read and write disk pack label suitable for Sun's OpenBoot PROM

 wall(1) - write a message to users

 wlconfig(8) - read/write wavelan config parameters

 write(1) - send a message to another user

 write(2), writev(2), pwrite(2), pwritev(2) - write output

 ExtUtils::Manifest(3) - utilities to write and check a MANIFEST file

 ExtUtils::Miniperl(3), writemain(3) - write the C code for perlmain.c

 ExtUtils::Mksymlists(3) - write linker options files for dynamic extension

 encoding(3) - allows you to write your script in non-ascii or non-utf8