Lab46 Wiki

Relational operators

• eq is equal to

• ne is not equal to

• le is less than or equal to

• lt is less than

• gt is greater than

• ge is greater than or equal to

*Remember your WildCards!!! (?*[ ][ *])

Regular Expressions

• match any single symbol
• 0 or more of the previous
• [] character class match one of any of the enclosed
• [^ ] inverted - do NOT match
• ^ match start of line
• $ match end of line
• \< match start of word
• \> match end of word

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• + one or more of the previous
• () grouping
• | OR

We were asked to preform a solution for a problem to rearrange our ls -l list like this :

[filename]:(perms), user/group.

the solution was:

ls -l | grep -v '^total' | sed 's/ */ /g' | sed 's/^\(……….\) [0-9][0-9]* \([a-z][a-z0-9]*\) \([a-z][a-z0-9]*\).* \(.*\)$/[\4]:(\1),\2\/\3/g'