Commands tagged email (22)

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Get contents from hosts, passwd, groups even if they're in DB/LDAP/other
getent allows to get the contents of several databases in their native file format even if they are not actually in /etc. For example, if you are using a LDAP or a DB to authenticate your users, you won't find their info by catting /etc/passwd, but "getent passwd" will concatenate /etc/passwd to the LDAP/DB.

fuman, an alternative to the 'man' command that shows commandlinefu.com examples
Example: fuman sed

list human readable files
include in the list human readable hidden files too: $ file .* *|grep 'ASCII text'|sort -rk2 more reliable command: $ ls|xargs file|grep 'ASCII text'|sort -rk2 and include hidden files: $ ls -a|xargs file|grep 'ASCII text'|sort -rk2

Welcome humans!
Some information about robots. :-)

List files accessed by a command
Can be run as a script `ftrace` if my_command is substrituted with "[email protected]" It is useful when running a command that fails and you have the feeling it is accessing a file you are not aware of.

Btrfs: Find file names with checksum errors
Btrfs reports the inode numbers of files with failed checksums. Use `find` to lookup the file names of those inodes. The files may need to be deleted and replaced with backups.

Determine if a command is in your $PATH using POSIX
it is generally advised to avoid using which(1) whenever possible. which(1) is usually a csh(1) script, or sometimes a compiled binary. It's output is highly variable from operating system to operating system, so platform independent scripts could become quite complicated with the logic. On HP-UX 10.20, for example, it prints "no bash in /path /path /path ..."; on OpenBSD 4.1, it prints "bash: Command not found."; on Debian (3.1 through 5.0 at least) and SuSE, it prints nothing at all; on Red Hat 5.2, it prints "which: no bash in (/path:/path:...)"; on Red Hat 6.2, it writes the same message, but on standard error instead of standard output; and on Gentoo, it writes something on stderr. And given all these differences, it's still variable based on your shell. This is why POSIX is king. See http://mywiki.wooledge.org/BashFAQ/081 for more ways on avoiding which(1).

Numeric zero padding file rename
This uses Perl's rename utility (you may have to call it as prename on your box) and won't choke on spaces or other characters in filenames. It will also zero pad a number even in filenames like "vacation-4.jpg".

Mount a VMware virtual disk (.vmdk) file on a Linux box
Assumes XP/2000/2003. For Server 2008+ try offset=105,906,176 You can find this number in the System Information utility under Partition Starting Offset. UEFI based boxes you want partition 2 since the first is just the boot files (and FAT). This works with (storage side) snapshots which is handy for single file restores on NFS mounted VMware systems

Colorize make, gcc, and diff output
Colorize output of make, gcc/g++ or diff, making it easier to read at a glance. They are not distributed with make, diff or gcc, but are usually available in the repositories.


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