Under KDE or Gnome desktop I get nice facility to search all man pages for particular command or phrase. I am login to remote server over the ssh session. How do I search all the man pages for a particular command at Linux shell prompt?
You need to use the following commands to search man pages:
apropos Command
The apropos command searches a set of database files containing short descriptions of system commands for keywords and shows the result on the screen. The syntax is as follows:
apropos keyword apropos "string or phrase" apropos -s 1 delete |
apropos Command Examples
To Search command / functions related to compare operation, enter:
$ apropos compare
Sample outputs:
[ (1) - check file types and compare values bcmp (3) - compare byte sequences bzcmp (1) - compare bzip2 compressed files bzdiff (1) - compare bzip2 compressed files cmp (1) - compare two files byte by byte comm (1) - compare two sorted files line by line compare (1) - mathematically and visually annotate the difference between an image and its reconstruction. diff (1) - compare files line by line diff3 (1) - compare three files line by line git-diff-files (1) - Compares files in the working tree and the index git-diff-index (1) - Compares content and mode of blobs between the index and repository git-diff-tree (1) - Compares the content and mode of blobs found via two tree objects infocmp (1) - compare or print out terminfo descriptions mcomp (1) - Compares two files using mtools memcmp (3) - compare memory areas msgcmp (1) - compare message catalog and template ndiff (1) - Utility to compare the results of Nmap scans ntfscmp (8) - compare two NTFS filesystems and tell the differences pthread_equal (3) - compare thread IDs strcasecmp (3) - compare two strings ignoring case strcmp (3) - compare two strings strcoll (3) - compare two strings using the current locale strncasecmp (3) - compare two strings ignoring case strncmp (3) - compare two strings strverscmp (3) - compare two version strings test (1) - check file types and compare values wcscasecmp (3) - compare two wide-character strings, ignoring case wcscmp (3) - compare two wide-character strings wcsncasecmp (3) - compare two fixed-size wide-character strings, ignoring case wcsncmp (3) - compare two fixed-size wide-character strings wmemcmp (3) - compare two arrays of wide-characters xzcmp (1) - compare compressed files xzdiff (1) - compare compressed files zcmp (1) - compare compressed files zdiff (1) - compare compressed files
Task: Search For a String
Search command to remove a file, enter:
$ apropos "remove file"
Sample outputs:
rm (1) - remove files or directorie
Task: Search Specific Section of The Man Page
To search only the given manual section use the -s option:
apropos -s 1 compare
Sample outputs:
[ (1) - check file types and compare values bzcmp (1) - compare bzip2 compressed files bzdiff (1) - compare bzip2 compressed files cmp (1) - compare two files byte by byte comm (1) - compare two sorted files line by line compare (1) - mathematically and visually annotate the difference between an image and its reconstruction. diff (1) - compare files line by line diff3 (1) - compare three files line by line git-diff-files (1) - Compares files in the working tree and the index git-diff-index (1) - Compares content and mode of blobs between the index and repository git-diff-tree (1) - Compares the content and mode of blobs found via two tree objects infocmp (1) - compare or print out terminfo descriptions mcomp (1) - Compares two files using mtools msgcmp (1) - compare message catalog and template ndiff (1) - Utility to compare the results of Nmap scans test (1) - check file types and compare values xzcmp (1) - compare compressed files xzdiff (1) - compare compressed files zcmp (1) - compare compressed files zdiff (1) - compare compressed files
Task: Regex Based Search
You can force apropos to interpret each keyword as a regular expression using the -r option:
$ apropos -r scanf
Sample outputs:
fscanf (3) - input format conversion scanf (3) - input format conversion sscanf (3) - input format conversion Video::DVDRip::CPAN::Scanf (3pm) - emulate sscanf() of the C library vfscanf (3) - input format conversion vscanf (3) - input format conversion vsscanf (3) - input format conversion
The ‘man -K’ Command
The -K option is passed to the man command to search for the specified string in all man pages. The syntax is as follows:
man -K keyword man -K "string or phrase" |
Search all man pages for fopen word, type:
$ man -K "fopen"
Output:
/usr/share/man/en/man3/fclose.3.gz? [ynq]
Type y to open/display man page, n to continue search, q to Quit search. This is a brute-force search, and is likely to take some time. So it helps to specify a man page section (1-7) using the following syntax:
$ man -s 3 -K "open"
OR
$ man -s 8 -K "user"
Please note that above commands also works with other UNIX and *BSD like oses
