cmdarg ====== cmdarg is a helper library I wrote for bash scripts because, at current, option parsing in bash (-foo bar, etc) is really hard, lots harder than it should be, given bash's target audience. So here's my solution. There are 4 functions you will care about: cmdarg cmdarg_info cmdarg_parse cmdarg_usage cmdarg ====== This function is used to tell the library what command line arguments you accept. Check cmdarg.sh for the latest syntax. cmdarg 'l:' 'source_ldap' 'Source (old) LDAP URI' cmdarg 'u:' 'source_ldap_username' 'Source (old) LDAP Username' cmdarg 'c:' 'groupmap' 'A CSV file mapping usernames to groups that they should belong to post-conversion' '' 'test -e $OPTARG' All arguments are OPTIONAL by default. An argument that has ':' on the end of its single character option, and does not specify a default value (empty string is considered "not specified"), is REQUIRED. cmdarg_info =========== This function sets up information about your program for use when printing the help/usage message. Again, see cmdarg.sh for the latest syntax. cmdarg_info "header" "Convert existing LDAP users to the new LDAP server/schema." cmdarg_info "author" "Some Poor Bastard " cmdarg_info "copyright" "(C) 2013" cmdarg_parse ============ This command does what you expect, parsing your command line arguments. However you must pass your command line arguments to it. Generally this means: cmdarg_parse "$@" ... Beware that "$@" will change depending on your context. So if you have a main() function called in your script, you need to make sure that you pass "$@" from the toplevel script in to it, otherwise the options will be blank when you pass them to cmdarg_parse. Any argument parsed that has a validator assigned, and whose validator returns nonzero, is considered a failure. Any REQUIRED argument that is not specified is considered a failure. For every argument, a global associative array "cmdarg_cfg" is populated with the long version of the option. E.g., in the example above, '-c' would become ${cmdarg_cfg['groupmap']}, for friendlier access during scripting. I love it when a plan comes together ==================================== Given some code like this: cmdarg_info "header" "Convert existing old LDAP users to the new LDAP server/schema." cmdarg_info "author" "Some Poor Bastard " cmdarg_info "copyright" "(C) 2013" cmdarg 'C:' 'cfgfile' 'Config file that contains options that should be used in place of command line args' '' 'test -e $OPTARG' cmdarg 'c:' 'groupmap' 'A CSV file mapping usernames to groups that they should belong to post-conversion' '' 'test -e $OPTARG' cmdarg 'l:' 'source_ldap' 'Source (old) LDAP URI' cmdarg 'u:' 'source_ldap_username' 'Source (old) LDAP Username' cmdarg 'p:' 'source_ldap_password' 'Source (old) LDAP Password' cmdarg 'b:' 'source_ldap_basedn' 'Source (old) LDAP Base DN (ou=x,dc=x,dc=x)' cmdarg 'o:' 'source_ldap_ou_users' 'Source (old) LDAP ou for Users' 'users' cmdarg 'g:' 'source_ldap_ou_groups' 'Source (old) LDAP ou for Groups' 'groups' cmdarg 'L:' 'dest_ldap' 'Destination (new) LDAP URI' cmdarg 'U:' 'dest_ldap_username' 'Destination (new) LDAP Username' cmdarg 'P:' 'dest_ldap_password' 'Destination (new) LDAP Password' cmdarg 'B:' 'dest_ldap_basedn' 'Destination (new) LDAP Base DN (dc=x,dc=x)' cmdarg 'O:' 'source_ldap_ou_users' 'Destination (new) LDAP ou for Users' 'users' cmdarg 'G:' 'source_ldap_ou_groups' 'Destination (new) LDAP ou for Groups' 'groups' cmdarg 's:' 'slappasswd_salt' 'Slappasswd salt format (man slappasswd)' 'rofflewaffles%s' cmdarg 'S:' 'slappasswd_scheme' 'Slappasswwd hash scheme to use (CRYPT|MD5|SMD5|SSHA|SHA)' 'SSHA' 'echo $OPTARG | grep -E "CRYPT|MD5|SMD5|SSHA|SHA" >/dev/null 2>&1' cmdarg_parse "$@" ... Here's what we can expect to see from the usage message: $ ./ldap-convert.sh -h ldap-convert.sh (C) 2013 : Some Poor Bastard Convert existing LDAP users to the new LDAP server/schema. Required Arguments: -C : Config file that contains options that should be used in place of command line args -c : A CSV file mapping usernames to groups that they should belong to post-conversion -l : Source (old) LDAP URI -u : Source (old) LDAP Username -p : Source (old) LDAP Password -b : Source (old) LDAP Base DN (ou=x,dc=x,dc=x) -L : Destination (new) LDAP URI -U : Destination (new) LDAP Username -P : Destination (new) LDAP Password -B : Destination (new) LDAP Base DN (dc=x,dc=x) Optional Arguments: -o : Source (old) LDAP ou for Users (Default "users") -g : Source (old) LDAP ou for Groups (Default "groups") -O : Destination (new) LDAP ou for Users (Default "users") -G : Destination (new) LDAP ou for Groups (Default "groups") -s : Slappasswd salt format (man slappasswd) (Default "rofflewaffles%s") -S : Slappasswwd hash scheme to use (CRYPT|MD5|SMD5|SSHA|SHA) (Default "SSHA") ... And if we run it without '-h', then the argument parser (rather helpfully) tells us which arguments we've failed to specify, before printing the help: $ ./ldap-convert.sh Invalid value for -c : Invalid value for -C : Missing arguments : -C -c -l -u -p -b -L -U -P -B ldap-convert.sh (C) 2013 : Some Poor Bastard Convert existing LDAP users to the new LDAP server/schema. Required Arguments: -C : Config file that contains options that should be used in place of command line args -c : A CSV file mapping usernames to groups that they should belong to post-conversion -l : Source (old) LDAP URI -u : Source (old) LDAP Username -p : Source (old) LDAP Password -b : Source (old) LDAP Base DN (ou=x,dc=x,dc=x) -L : Destination (new) LDAP URI -U : Destination (new) LDAP Username -P : Destination (new) LDAP Password -B : Destination (new) LDAP Base DN (dc=x,dc=x) Optional Arguments: -o : Source (old) LDAP ou for Users (Default "users") -g : Source (old) LDAP ou for Groups (Default "groups") -O : Destination (new) LDAP ou for Users (Default "users") -G : Destination (new) LDAP ou for Groups (Default "groups") -s : Slappasswd salt format (man slappasswd) (Default "rofflewaffles%s") -S : Slappasswwd hash scheme to use (CRYPT|MD5|SMD5|SSHA|SHA) (Default "SSHA") ... And here's what the cmdarg_cfg associate array winds up holding, illustrated with some debug prints: $ ./ldap-convert.sh -c ./users_groups_map.csv -l 1 -u 1 -p 1 -b 1 -L 1 -U 1 -P 1 -B 1 cmdarg_cfg[groupmap]="./users_groups_map.csv" cmdarg_cfg[slappasswd_salt]="rofflewaffles%s" cmdarg_cfg[source_ldap_ou_groups]="groups" cmdarg_cfg[slappasswd_scheme]="SSHA" cmdarg_cfg[dest_ldap_username]="1" cmdarg_cfg[dest_ldap_password]="1" cmdarg_cfg[source_ldap_password]="1" cmdarg_cfg[source_ldap_username]="1" cmdarg_cfg[cfgfile]="/dev/null" cmdarg_cfg[dest_ldap_basedn]="1" cmdarg_cfg[source_ldap_basedn]="1" cmdarg_cfg[source_ldap_ou_users]="users" cmdarg_cfg[source_ldap]="1" cmdarg_cfg[dest_ldap]="1"