Expr command
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| + | You are here: '''[[Main_Page|DD-WRT wiki mainpage]] / [[Telnet/SSH_and_the_Command_Line|SSH/Telnet & The CLI]] / expr ''' | ||
| + | |||
| '''expr''' is the expression command in bourne type shells. On the WRT, expr is handled by busybox. | '''expr''' is the expression command in bourne type shells. On the WRT, expr is handled by busybox. | ||
| Line 4: | Line 6: | ||
| - | ~ # '''expr 5 6''' | + | ~ # '''expr 5 6''' |
| - | + | 11 | |
| - | 11 | + | |
| - | + | ||
| - | + | ||
| - | 9 | + | ~ # '''expr 39 / 4''' |
| + | 9 | ||
| + | Loop counter example: | ||
| + | #!/bin/sh | ||
| + | |||
| + | # while lc < 10 do | ||
| + | |||
| + | lc=1 | ||
| + | while [ $lc -lt 10 ] ; do | ||
| + | lc=`expr $lc + 1` | ||
| + | echo LoopCount: $lc | ||
| + | done | ||
| Try '''expr --help''' for more details. | Try '''expr --help''' for more details. | ||
Revision as of 19:00, 9 January 2009
You are here: DD-WRT wiki mainpage / SSH/Telnet & The CLI / expr
expr is the expression command in bourne type shells. On the WRT, expr is handled by busybox.
expr takes expressions. The most common expressions deal with simple arithmetic operations:
~ # expr 5 6 11
~ # expr 39 / 4 9
Loop counter example:
#!/bin/sh # while lc < 10 do lc=1 while [ $lc -lt 10 ] ; do lc=`expr $lc + 1` echo LoopCount: $lc done
Try expr --help for more details.