expr - manual page for expr 1.31.1
BusyBox v1.31.1 (2020-04-30 13:38:01 EDT) multi-call binary.
Print the value of EXPRESSION to stdout
- ARG1 | ARG2
- ARG1 if it is neither null nor 0, otherwise ARG2
- ARG1 & ARG2
- ARG1 if neither argument is null or 0, otherwise 0
- ARG1 < ARG2
- 1 if ARG1 is less than ARG2, else 0. Similarly:
- ARG1 <= ARG2 ARG1 = ARG2 ARG1 != ARG2 ARG1 >= ARG2 ARG1 > ARG2
ARG1 + ARG2 Sum of ARG1 and ARG2. Similarly: ARG1 - ARG2 ARG1 * ARG2 ARG1
/ ARG2 ARG1 % ARG2 STRING : REGEXP Anchored pattern match of REGEXP in
STRING match STRING REGEXP Same as STRING : REGEXP substr STRING POS
LENGTH Substring of STRING, POS counted from 1 index STRING CHARS Index in
STRING where any CHARS is found, or 0 length STRING Length of STRING quote
TOKEN Interpret TOKEN as a string, even if
- it is a keyword like 'match' or an
- operator like '/'
- Value of EXPRESSION
Beware that many operators need to be escaped or quoted for
shells. Comparisons are arithmetic if both ARGs are numbers, else
lexicographical. Pattern matches return the string matched between \( and \)
or null; if \( and \) are not used, they return the number of characters
matched or 0.