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This article mainly explains "how to search multiple strings with grep". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to search multiple strings with grep.

Grep is a powerful command-line tool that allows you to search for lines that match regular expressions in one or more files and write the matching results to standard output.

Grep's Multi-conditional search Model

Grep supports three regular expression grammars: Basic, Extended, and Perl regular expressions. When no regular expression type is specified, grep interprets the search pattern as a Basic basic regular expression.

Use the | pipe character when using the multi-conditional search mode. Use grep's basic regular expression to search for multiple conditions, with the following syntax:

] # grep 'pattern1\ | pattern2' file

When using basic regular expressions, you need to escape using the\ escape character as | pipe character.

If you use extended mode, you can add the-E parameter. Using extension mode, there is no need to add escape characters for the | pipe character. You can also use the egrep command, which is used in the same way as grep-E.

] # grep 'pattern1 | pattern2' file] # egrep' pattern1 | pattern2' file

Use an example

Check whether the operating system has virtualization enabled and use Basic basic mode:

[root@localhost ~] # grep 'vmx\ | svm' / proc/cpuinfo flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch ssbd ibrs ibpb stibp tpr_shadow vnmi ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 invpcid Rtm mpx rdseed adx smap clflushopt xsaveopt xsavec arat spec_ctrl intel_stibp flush_l1d arch_capabilities

If you use the extension mode, you don't need to add the\ escape character, the way the extension mode is used:

[root@localhost ~] # grep-E 'vmx | svm' / proc/cpuinfo flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch ssbd ibrs ibpb stibp tpr_shadow vnmi ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 invpcid Rtm mpx rdseed adx smap clflushopt xsaveopt xsavec arat spec_ctrl intel_stibp flush_l1d arch_capabilities# or [root@localhost ~] # egrep 'vmx | svm' / proc/cpuinfo flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_ Lm abm 3dnowprefetch ssbd ibrs ibpb stibp tpr_shadow vnmi ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec arat spec_ctrl intel_stibp flush_l1d arch_capabilities

By default, grep is case-sensitive. If you need to ignore case, you can add the-I parameter:

[root@localhost ~] # grep-E-I 'VMX | SVM' / proc/cpuinfo flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch ssbd ibrs ibpb stibp tpr_shadow vnmi ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep Bmi2 invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec arat spec_ctrl intel_stibp flush_l1d arch_capabilities# or [root@localhost ~] # egrep-I 'VMX | SVM' / proc/cpuinfo flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c Rdrand hypervisor lahf_lm abm 3dnowprefetch ssbd ibrs ibpb stibp tpr_shadow vnmi ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec arat spec_ctrl intel_stibp flush_l1d arch_capabilities

Summary

Grep is a powerful command-line tool that allows you to search for lines that match regular expressions in one or more files and write the matching results to standard output.

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