I.

./regexp 'aaa' zzzzzaaaaaaaacccccc
Correspondance !


le x{y,} x le caractère et y le nombre de caractère:

./extregexp 'a{3,}' bbbbbaaaaacccccc
Correspondance !
il y a au moins 3 a donc il y a correspondance.

./extregexp 'a{6,}' "zzzzzaaaaaccccc"
Pas de correspondance.
il y a 5 a et non 6 donc pas de correspondance

./regexp '\baaa' zzzzzaaaaaaaccccc
Pas de correspondance.

./regexp '\baaa' "zzzzz aaaaaccccc"
Correspondance !

III)

1.
grep "\.ipv[46]\." sysctl.conf

net.ipv4.tcp_syncookies = 1
#net.ipv4.conf.all.log_martians = 1
#net.ipv4.conf.all.accept_redirects = 0
#net.ipv4.conf.all.accept_source_route = 0
#net.ipv6.conf.all.accept_redirects = 0
#net.ipv6.conf.all.accept_source_route = 0
net.ipv4.ip_forward = 0
net.ipv6.conf.all.forwarding = 0
net.ipv6.conf.default.use_tempaddr = 2
net.ipv6.conf.all.use_tempaddr = 2
#net.ipv4.ip_local_port_range = 32768    61000



2.
grep -v "^#" sysctl.conf  /   grep '^[^#]' sysctl.conf


net.ipv4.tcp_syncookies = 1



net.ipv4.ip_forward = 0
net.ipv6.conf.all.forwarding = 0

net.ipv6.conf.default.use_tempaddr = 2
net.ipv6.conf.all.use_tempaddr = 2





kernel.sysrq = 0


3.
grep -i "_root_" ca_certificates.conf

mozilla/America_Online_Root_Certification_Authority_1.crt
mozilla/America_Online_Root_Certification_Authority_2.crt
mozilla/Certum_Root_CA.crt
mozilla/Chambers_of_Commerce_Root_-_2008.crt
mozilla/DST_Root_CA_X3.crt
mozilla/Deutsche_Telekom_Root_CA_2.crt
mozilla/DigiCert_Assured_ID_Root_CA.crt
mozilla/DigiCert_Global_Root_CA.crt
mozilla/DigiCert_High_Assurance_EV_Root_CA.crt
mozilla/Entrust_Root_Certification_Authority.crt
mozilla/Firmaprofesional_Root_CA.crt
mozilla/GlobalSign_Root_CA.crt
mozilla/GlobalSign_Root_CA_-_R2.crt
mozilla/GlobalSign_Root_CA_-_R3.crt
mozilla/Global_Chambersign_Root_-_2008.crt
mozilla/Go_Daddy_Root_Certificate_Authority_-_G2.crt
mozilla/Hongkong_Post_Root_CA_1.crt
mozilla/Microsec_e-Szigno_Root_CA.crt
mozilla/Microsec_e-Szigno_Root_CA_2009.crt
mozilla/OISTE_WISeKey_Global_Root_GA_CA.crt
mozilla/QuoVadis_Root_CA.crt
mozilla/QuoVadis_Root_CA_2.crt
mozilla/QuoVadis_Root_CA_3.crt
mozilla/RSA_Root_Certificate_1.crt
mozilla/S-TRUST_Authentication_and_Encryption_Root_CA_2005_PN.crt
mozilla/Security_Communication_Root_CA.crt
mozilla/Sonera_Class_1_Root_CA.crt
mozilla/Sonera_Class_2_Root_CA.crt
mozilla/Staat_der_Nederlanden_Root_CA.crt
mozilla/Staat_der_Nederlanden_Root_CA_-_G2.crt
mozilla/Starfield_Root_Certificate_Authority_-_G2.crt
mozilla/Starfield_Services_Root_Certificate_Authority_-_G2.crt
mozilla/Swisscom_Root_CA_1.crt
mozilla/TDC_Internet_Root_CA.crt
mozilla/TDC_OCES_Root_CA.crt
mozilla/TURKTRUST_Certificate_Services_Provider_Root_1.crt
mozilla/TURKTRUST_Certificate_Services_Provider_Root_2.crt
mozilla/TWCA_Root_Certification_Authority.crt
mozilla/UTN_DATACorp_SGC_Root_CA.crt
mozilla/UTN_USERFirst_Email_Root_CA.crt
mozilla/UTN_USERFirst_Hardware_Root_CA.crt
mozilla/VeriSign_Universal_Root_Certification_Authority.crt
mozilla/WellsSecure_Public_Root_Certificate_Authority.crt
mozilla/Wells_Fargo_Root_CA.crt
mozilla/certSIGN_ROOT_CA.crt
mozilla/ePKI_Root_Certification_Authority.crt
mozilla/thawte_Primary_Root_CA.crt
mozilla/thawte_Primary_Root_CA_-_G2.crt
mozilla/thawte_Primary_Root_CA_-_G3.crt

4.