Use getpwnam group of functions. Example code: #include <sys/types.h> #include <pwd.h> #inc... For gid, use getgrnam

Start gdb with the executable and coredump: $ gdb <path to executable> core While in the debugger, use the following commands: (gdb) where ("shows a summary of the stack") ... Example debug session from Debugging Under Unix: gdb Tutorial : Use backtrace (or bt ) to see the callstack: (gdb) backtrace #0 Node<int>::next (this=0x0) ... Inspect the value of item_to_remove at address 0xffbef014 (the value is 1): (gdb) x 0xffbef014 0xffbef014: 0x00000001 (g... Note: The program must be compiled with the debug switch -g in order to see the source code. More resources: Linux software debugging with GDB Debugging with gdb

By default Linux pipe output is buffered. For example, you can't see the most recent stdout on screen with tee : $ ./mycommand | tee /tmp/mycommand.log Here are two ways to make the pipe unbuffered. Method 1: use the unbuffer command from expect $ sudo apt-get install expect-dev $ unbuffer ./... Method 2: use stdbuf # Make output line buffered: $ stdbuf -oL ./myc...

$ var='variable to be truncated' $ echo ${var#v...

According to wikipedia , only two characters are invalid in a file name: In Unix-like file systems the null character, as that is the end-of-string indicator and the path separator / are prohibited.

To zip all files under js and css , but exclude the svn files: $ zip -r css-js.zip css js -x '*.svn*'

Shell functions are declared using this syntax: [ function ] name () compound-command [ redirectio... Example: function ll { ls -alF $* } Example 2: ll() { ls -alF $* } Shell functions can be exported to subshells with the -f switch: $ export -f ll However , I had problems logging in Ubuntu 11.10 after I added this to .profile : export -f ll

This is the command to print all regular files in the src folder but excluding all files within the .svn folders: $ find src -name .svn -prune -o -type f -print where -o is the or operator. Define a shortcut: ff () { find $1 -name .svn -prune -o -...

You can use either declare or typeset to list function definitions : To list all function names: declare -F To display a function definition: $ declare -f quote quote () { echo ... If you see a lot of functions with names starting with the underscore ( _ ) and wonder where they come from, they are created by the scripts in /etc/bash_completion.d/ .

The C shell allows you to define aliases with arguments: \!^ passes the first argument, \!* passes all arguments. Examples from http://unixhelp.ed.ac.uk : alias print 'lpr \!^ -Pps5' alias print 'lp... In ksh or bash you cannot define alias with arguments. Use function instead.